Would vs Used to

1). Used to can refer to repeated actions and events in the past, in the same way as would.

e.g

Sometimes he used to bring me little presents without saying why.

Sometimes he would bring me little presents without saying why.

2). Only used to, not would can refer to past states.

e.g

I used to have an old Rolls-Royce. (NOT - I would have an old Rolls-Royce.)

3). We use used to, not would, to talk about regular and important habitual behaviour.

e.g

I used to smoke. (NOT- I would smoke.)

Would - Uses

Would is a modal auxiliary verb.
Would is used as a softer less definite form of will, in some cases as past of will.

1). In indirect speech, would is used after past reporting verbs where will was used in direct speech.

e.g

Tomorrow will be fine - DIRECT
The forcast said the next day would be fine - INDIRECT

2). Future in past tense - Would is used to express the idea of "future in the past" - to talk about a past action which had not yet happened at the time we are talking about.

e.g

In Berlin, he first met the woman he would one day marry.
There was a chance that my letter would arrive in time.

3). Would is used in polite requests and offers as a softer form of will.

e.g

Would you open the window, please?
If you would come this way.....

4). Would can refer to past willingness of a general kind, but not to willingness to do something on a particular past occassion.

e.g

She would hoover, dust and iron, but she didn't like doing windows.
She agreed to come and see me . (NOT - She would come and see me)

But would not can be used to refer to a refusal on a particular past occassion.

e.g

I asked her very politely, but she wouldn't tell me.

5). Conditional auxiliary: I would....if - Would is often used as an auxiliary with verbs that refer to unnreal or uncertain situations - for example in sentences with if.

e.g

I would tell you if I knew.
It would have been nice if he'd thanked you.

6). Typical behaviour - Would is used as the past of will to talk about typical behaviour in the past.

e.g

When she was old, she would sit in the corner talking to herself for hours.

Sentences with stressed would can be used to criticise people's behaviour.

e.g

He was a nice boy, but he would talk about himself all the time.

Stressed would can also be used to criticise a single past action - the meaning is ' that's typical of you '

e.g

You would tell Sania about the party - I didn't want to invite her.

Ago vs Since

Ago vs. Since

Both words speak of the past, and they are often used interchangeably.

Ago: from the present to the past. It is used after the word or phrase it modifies, especially with the simple past tense, not with the perfect tense.

e.g. It happened a few minutes ago.

Since: from the past to the present. It is used with the present or past perfect tense.

e.g. I haven't eaten since breakfast.

Compare to vs. Compare with

Compare to is used to liken two things or to put them in the same category. You should use compare to when you intend to simply assert that two things are alike. Use compare to to illustrate that two things are similar.

1. The economy can be compared to a stallion charging at the gate.
2. I compare getting comments from students in class to pulling teeth.
3. She compared her work for women's rights to Susan B. Anthony's campaign for women's suffrage.

Compare with is used to place two things side by side for the purpose of examining their similarities or differences. Use compare with to illustrate the differences a comparison draws.

1. The American economy can be compared with the European economy to note how military history impacts future economics.
2. It would be interesting to compare Purdue with Ohio State.
3. Ann has a 3.5 GPA, compared with Jim's 2.9.

Agreement of Verb with Collective Nouns

In my post on Subject Verb Agreement I had already mentioned this rule. On request from many students, I am explaining this particular concept in detail.

A collective noun is a noun that represents a group or a collection of objects usually considered as a unit. Words like crowd, troop, herd, people, flock, and jury are collective nouns.

A collective noun that is singular in meaning requires a singular verb. A collective noun that is plural in meaning requires a plural verb.

If the collective noun in a particular sentence represents the individuals acting as a unit, the noun is singular. If the sentence indicates clearly that the individuals are acting seperately, the noun is plural.

e.g -

1). The committee is opposed to the plan. (acting as a unit)
2). The board of directors is in session. (as a unit)
3). The jury returned its verdict. (as a unit)
4). The jury have returned to their homes. (as individuals)
5). The family have given their contributions. (as individuals)

In most cases where the individuals composing a group are acting seperately, it is better to use such expressions as the members of the jury, the members of the family, etc. These expressions sound better and clearly indicate that the individuals are acting seperately.

1). The members of the jury have returned to their homes.
2). The members of the band wore their uniforms.
3). The people in the audience waved their hands.

Special case of Agreement

The words like "half" , "part" etc are singular or plural according to the meaning of the sentence. When these words refer to a mass or a section, they are singular. When they refer to a number of individuals or things, they are plural.

e.g -

1. Half of the boys are in camp. (number -- plural)
2. Half of the pie is left. (mass or section -- singular)
3. Part of the roof was destroyed. (mass or section -- singular)
4. Part of the guests have arrived. (number -- plural)

Do vs Make

1. Do - for indefinite activities e.g with words like thing, something, nothing, anything, what. e.g

a). Do something!
b). What shall we do?
c). Then Ram did a very strang thing.

2. Do - when we talk about work and jobs. e.g

a). I'm not going to do any work today.
b). It's time to do the accounts.
c). I would't like to do your job.

3. We use do...... ing structure to talk about activities that take a certain time, or are repeated. Usually there is a determiner (e.g the, my, some ) before the -ing form. Verb after do cannot have object in this structure.But do can be used with a compound noun that includes verb + object. e.g

a). During the holidays I'm going to do some walking and a lot of reading.
b). I'm going to watch some TV.
c). I want to do some bird-watching this weekend.

4. Make - we use make to talk about constructing, building, creating etc.e.g

a). My father and I once made a boat.
b). Let's make a plan.

5. Common fixed expressions

do good, harm, business, one's best, a favour, sport, exercise, one's hair, one's teeth, one's duty.

make a journey, an offer, arrangements, a suggestion, a decision, an attempt, an effort, an excuse, an exception, a mistake, a noise, a phone call, money, a profit, a fortune, peace, love, war, bed, a fire, progress.

6. After make + object, we use the infinitive without to. e.g

I made her cry. (not - I made her to cry. or I made her crying)

The infinitive must follow the object. e.g

I can't make the television work. ( not - I can't make work the television)

In passive constructions the infinitive with to is used. e.g

Ram was made to repeat the whole story.

7. In some cases make can be followed by myself, yourself etc and a past participle. This structure is common with understood and heard. e.g

She had to shout to make herself heard.

8. We can talk about an effect or change with make + object + adjective/noun . e.g

The rain made the grass wet. ( not - The rain made wet the grass).

We do not use make ... be in this structure.

You have made me a happy man. ( not - You have made me be a happy man).

Do - Substitute verb

Do - Substitute Verb - (auxiliary verb + do) - In British English (but not American), do can be used alone as a substitute verb after an auxiliary verb. e.g

a). He smokes more than he used to - American english
He smokes more than he used to do.- British English

b). Do you think Phil will come? ~ He might.- American english
Do you think Phil will come? ~ He might do.- British English

Do - auxiliary verb

The auxiliary verb "do" - followed by infinitives without "to". It has several uses, one of them -- Ellipsis

In cases where an auxiliary verb is used instead of a whole verb phrase, "do" is common in affirmative clause, questions and negatives. e.g

a). She doesn't like singing , but I do.
b). You saw Ram, didn't you?
c). Emil thinks there's something wrong with Ann, and so do I.


NOTE -

An auxiliary verb combines with another verb to help form the tense, mood, voice, or condition of the verb it combines with.
The verbs to have, to be, to do, will, shall, would, should, can, may, might, and could are the common auxiliary verbs in English.
Auxiliary verbs are sometimes called helping verbs.

Ellipsis - We often leave out words to avoid repetition, or in other cases when the meaning can be understood without them. This is called ellipsis.

Less vs Fewer

1). Less and Fewer -- Difference -

Less is the comparative of little ( used especially before uncountable nouns).

e.g - I earn less money than you.

Whereas

Fewer is the comparative of few ( used before plural nouns)

e.g - I've got fewer problems than I used to have.

2). Less of and fewer of - used before determiners such as the,, my, this and before pronouns.

e.g - At the college reunions, there are fewer of us each year.
I'd like to spend less of my time answering mails.

* Before nouns without determiners, of is not used.

e.g - If you want to lose weight, eat less food. (NOT less of food)

3). Nouns can be dropped after less and fewer if the meaning is clear.

e.g - Some people go to church, but less/fewer than 20 years ago

* Less can be used as an adverb (the opposite of adverb more)

e.g - I worry less than I used to.

4). Lesser - used to mean "smaller" or "not so much"

e.g - the lesser of two evils.

GMAT Examples - Sentence No 49 at the link below
http://gmatsentencecorrection.blogspot.com


5) Use less when referring to statistical or numerical expressions.
e.g:
Sara is less than five feet tall
Your issue essay should be a thousand words or less

NOTE: It's possible to regard the quantities as sums of countable measures

When to use the Passive voice ????

Active voice is the better form to use. As a rule, the active voice is preferred for business writing, and for any other form of writing that requires the direct approach. The use of active voice increases vividness.

However, the passive voice is generally used when the subject of the sentence is indefinite, general, or unimportant. In the sentence, They mine coal in Pennysylvania, the subject is so indefinite that it is not clear what is meant by they. It might mean the miners, the people, or the companies.This sentence, and sentences like it, are improved by putting the verb in the passive voice.

They mine coal in Pennysylvania. (Poor)
Coal is mined in Pennysylvania. (Better)

They grow wheat in many of our states. (Poor)
Wheat is grown in many of our states. (Better)

The passive voice is also used when what was done is more important than doer of the action. Study the following sentences:

The play, "Man and Superman," was written by Shaw. (Passive)
Shaw wrote the play "Man and Superman." (Active)

America was discovered by Columbus. (Passive)
Columbus discovered America. (Active)

In the first sentence, if you wish to emphasize the play more than the author, put the verb in the passive voice. In the third sentence , if you wish to emphasize the discovery more than the discoverer, put the verb in the passive voice.

The use of the passive voice is generally used when you want to emphasize the receiver rather than the doer. However, in the majority of cases the active voice is more effective than the passive voice.

Note - In general, one should avoid passive voice in GMAT, passive voice form may appear in a correct answer choice - especially in science, medical and technical writing styles.

The passive voice is required when the non - underlined part of the sentence contains the person or agent performing the action preceded by the word by.

e.g - The shuttle launch seen around the world by people of all ages, all races, and all religions.

This sentence is missing a verb, and it is therefore a fragment. Because the people who are seeing the launch are at the end of the sentence, preceded by the word by, we must use the passive voice to complete this sentence:

The shuttle launch WAS seen sround the world by people of all ages, all races, and all religions.

The link below also deals with usage of passive in GMAT sentence correction
Link to test magic forum - passive construction on GMAT

Forms of Verb 1 - Infinitive

What is infinitive form of verb? - It is of the form to + simple form of verb.e.g - to take ; to surprise.

Uses of the Infinitive -

1). After a verb - Verbs such as want, promise, plan, manage, forget, choose, prove, hope, pretend, need, expect, decide are followed immediately by an infinitive.

They expect to win the game.
She needs to apply for a scholarship.

2). After verb and object - With verbs that take an object, such as force, allow, believe, need, persuade, urge, expect, want, the infinitive follows the object.

She persuaded us to wait.
She urged her supporters not to leave.

3). After certain adjectives and nouns - Adjectives such as anxious, sorry, easy, difficult, right, wrong, can be followed by infinitives.

It is easy (for you) to get to my house.
He was eager to meet his new boss.

Some nouns (such as way, place, time, decision, job, aim) are frequently followed by an infinitive.

He has no place to relax.
It is time to go.

4). To express purpose

He is working at night (in order) to earn more money.

The Infinitive Without to

The infinitive form without to is used in the following idiomatic expressions.

1). After a causative make, let , have + object

He made his sister drive the whole way.
He had her pay for the gas, too.

2). After the verb help

They helped us solve the problem.

Whether vs. If

Using Whether and If


1). After Prepositions , we use only whether.

• I haven't settled the question of whether I'll go back home.
• There was a big argument about whether we should move to a new house.

2). Whether, not if, is used before infinitives.

• They can't decide whether to get married now or wait.

3). When a question-word clause is a subject or complement, whether is preferred.

• Whether we can stay with my mother is another matter. - (Subject)
• The question is whether the man can be trusted. - (Complement)
• The question is if the man can be trusted. - Correct but less preferred.

4). If an indirect question is fronted , whether is used.

• Whether I'll have time I'm not sure at the moment.

5). Whether is generally preferred in a two-part question with or.

• The Directors have not decided whether they will recommend a dividend or reinvest the profits.

6). After verbs that are more common in a formal style, whether is preferred.

• We discussed whether we should close the shop.

7). Whether and if both can introduce indirect questions.

• I'm not sure whether/ if I'll have time.

8). Yes/ No questions are reported with if or whether.

• I don't know if/ whether I can help you.

Note - The word IF does not always signal a conditional sentence. In such cases, GMAT prefers "whether" instead of "if"

• I don't know if I will go to the dance. (Incorrect)
• I don't know whether I will go to the dance. (Correct)

Click on link below and view sentence no. 45 and 46 for the above rule.
http://gmatsentencecorrection.blogspot.com

because vs. because of

1). Because is a conjunction, used at the beginning of a clause, before a subject and a verb.

We were late because it rained.
I'm happy because I met you.

2). Because of  is a two - word preposition used before a noun or a pronoun.

We were late because of the rain.
I'm happy because of you.

Note: "Because" and its clause can go after or before the main clause.

I finished early because I worked fast.
Because I worked fast, I finished early.


View sentence number 48 at the link below
http://gmatsentencecorrection.blogspot.com

It -- as subject of a sentence

The Third Person It as Subject of a sentence

It as a subject of a sentence can be used in two different ways.

1). As an empty or meaningless word in expressions that concern the time or the weather:

It is one o'clock.
It is raining.
It will soon be supper time.
It is frosty.

2). As the formal subject of a sentence, referring to the deferred real subject that follows the verb:

It is useless to wait. (deferred subject - to wait)
It is a pity that you must go. (deferred subject - that you must go)

In sentences where it refers to a deferred subject, the latter can be moved to the normal position preceding the verb;

To wait is useless.
That you must go is a pity.

Below is a link that further explains usage of It in simple language.
Using It

In spite of vs Despite

In spite of - used to express the idea of contrast.

A). In spite of - is used as a preposition. In spite of + noun means almost same as although + clause.

e.g - We went out in spite of the rain. ( = .... although it was raining.)

B). In spite of is the opposite of because of .

e.g - She passed her exams in spite of her teacher. => (She had a bad teacher)

She passed her exams because of her teacher. => (She had a good teacher).

C). In spite of cannot be followed directly by a that - clause. Instead we can use in spite of the fact that

e.g - He is a good company in spite of the fact that he talks all the time.

Note - In formal English, despite can be used in the same way as in spite of.

e.g

Sita went on working in spite of feeling unwell.-- Correct
Sita went on working despite feeling unwell.-- Correct

Using the Colon

Use a colon

1). To introduce a list coming at the end of sentence

Her house has four rooms: a kitchen, a parlor, a bedroom, and a bath-room.

2). To introduce an example or an explanation related to something just mentioned

The miser had only one desire: to see his gold coins.

3). To introduce a quotation (usually of more than one line) in an essay

4). After the salutation in a formal letter

5). To seperate hours from minutes when the time of day is shown in numerals.

Misusing the Colon

Do not use a colon

1). After such as or including

All of the old gang were there, including : Mush Head, Beaver, Sparky, and Mole.- Incorrect colon use

2). Directly after a form of verb be

The three most popular composers of classical music, according to the poll, are : Bach, Mozart, and Beethoven.- Incorrect colon use

3). Between a verb and its object or between a preposition and its object.

The tourists went to: Toronto, Montreal, and Quebec.- Incorrect colon use

Using the Semicolon

Use a semicolon

1). To join two independent clauses that are closely related in meaning

Some visitors thrive on activities; others seldom leave the lounge.

2). To join two independent clauses when the second begins with or includes a conjunctive adverb, such as however, for example, or in addition

Everyone agrees that nuclear warfare is horrible; several nations, however, continue to manufacture nuclear weapons.

3). To seperate main clauses linked by a conjunction if commas appear in the clauses

Early in the play, Samson, tormented by his bondage to the Phillistines, his blindness, and his fall from glory, laments his condition; but he is careful to blame himself, not God.

4). Between items in a series when one or more of the items include commas

The furniture consisted of a bed, with four large, shapeless pillows; five matching wooden chairs with upright backs; and a corner cupboard imported from Bristol, England.

Misusing Semicolons

Do not use semicolon

1). Between a phrase and the clause to which it belongs

We tinkered with the wiring of the loudspeakers; to increase the volume - Use of semiclon is incorrect here.

2). Between a subordinate clause and the main clause

Even though I was exhausted; I listened to his complaints for two hours.- Use of semicolon is incorrect here, we must use a comma here.

3). A semicolon to introduce a list

Her house has four rooms; a kitchen, a parlor, a bedroom, and a bathroom.- Use of semicolon is incorrect here, we must use a colon here.

Even if vs. Even though

Even if means whether or not and has to do with the conditions that may apply. Even if is used as a conjunction.(even alone cannot act as a conjunction).

Even though means despite the fact that and is a more emphatic version of though and although.

• Even though he lost his job as Math Teacher, he continued to teach in the college.  - describes a real situation where the Math teacher lost his job, but continues to teach in the college. When we attach even to though in this way, we are in effect saying: you may find this surprising but..

• Even if he loses his job as Math Teacher, I think he'll continue to teach in the college. - describes an unreal situation where we could substitute 'just supposing' for even if and say: just supposing he loses his job as Math teacher, he would still continue teaching in the college. 

Rather than vs Instead of

Rather than shows preference. This expression is generally used in 'parallel' structures. e.g - with two nouns, adjectives, adverbs, infinitives or -ing forms. 

e.g.

1). We ought to invest in machinery rather than buildings.
2). I prefer starting early rather than leaving things to the last minute.

When the main clause has a to - infinitive, rather than is usually followed by an infinitive without to or -ing form. 

e.g. - I decided to write rather than phone/phoning.

Instead of suggests that one person, thing or action replaces another. Instead is not used alone as a preposition; we use the two words instead of.
Instead of is not usually followed by an infinitive.

e.g.

1). I'll have tea instead of coffee, please.
2). I stayed in bed all day instead of going to work.
3). Amit was invited to the reception, but he was ill, so Akash went instead of him.

Note: Instead (without of) is an adverb. It begins or ends a clause usually.

e.g.  She didn't go to Greece after all. Instead, she went to America.


Usage: instead of + noun phrase. Instead of is only a preposition and can introduce only a phrase i.e no verb.

Usage: rather than + verb (or) rather than + noun. Further rather than can act as a preposition and can introduce a prepositional phrase or can act as a conjunction and introduce a clause

Mr. EGG explains the usage in simple way via cartoon on the link below: 
rather than usage


To understand the use of the above concept view questions 22 and 23 by clicking on the link below.

http://gmatsentencecorrection.blogspot.com/

Although vs Though vs Even though

Although - linking word - expresses the idea of contrast.

e.g. - Although Amit has a car, he doesn't often drive it.

The clause with although can come at the end.

e.g. - Although the cafe was crowded, we found a table. OR We found a table, although the cafe was crowded.

Though - is informal. It means the same as although.

e.g. - Though / Although I liked the sweater, I decided not to buy it.

We can use though at the end of a sentence.

e.g. - I liked the sweater. I decided not to buy it, though.

Even though - is stronger, more emphatic than although.

e.g. -
1). Ram looked quite fresh, even though he'd been playing cricket.
2). Even though you dislike Sanya, you should try to be nice to her.

Note - We can use in spite of the fact (that) in the same way as although.

e.g. -
I'm no better, although I've taken the pills.
OR
I'm no better in spite of the fact that I've taken pills.

Quick Tip only for GMAT -- Applicable most of the times but not always ...

Even though -- when the condition given is negative but the outcome/result is positive
e.g. -- Even though Ram hadn't studied, he passed the exam.

Although -- when the condition given is positive but the outcome/result is negative
e.g. -- Although Ram had studied very hard, he did not score well.

USAGE:

Mr. EGG explains the usage in simple way via cartoon on the link below: 
Although vs. Even though

Using Absolute Phrases

An absolute phrase -- is a modifier generally made from a noun or noun phrase and a participle. It can modify a noun or pronoun or the whole of the base sentence to which it is attached.

e.g - Teeth chattering, we waited for hours in the bitter cold.
Sails flapping, the boat tugged at its mooring.

The participle may be expanded into a participle phrase --

Sails flapping in the brisk morning breeze, the boat tugged at its mooring.

An absolute phrase with other combinations

1). Noun and adverb phrase - Ram sat back comfortable, feet up on the desk.

2). Noun and adjective - Muscles taut, he hefted the barbells to his chest.

3). Noun and adjective phrase - She waved to the crowd, her face radiant with triumph.

4). Noun and adverb - Shoulders hunched, Ronaldo zigzagged past the linebacker.

We can use various absolute phrases in succession - Hair golden, eyes blue, body slender and tanned, he personified the California look.

Note - We can put an absolute phrase at the beginning of a sentence or at the end, setting it off with a comma.

We can also put an absolute phrase in the middle.

e.g - The speaker, his voice trembling with rage, denounced the hecklers. (note the pair of commas)

See the sentence number 14 at the link below

gmatsentencecorrection

Tenses - 1

If an action began in the past and continues into the present, use the present perfect tense.(Present Perfect = HAVE/ HAS + Past participle).

e.g - We have lived in a big mansion for five days.
(We lived in a big mansion for five days and still live there today)

If an action precedes an earlier past action, use the past perfect tense.(Past Perfect = HAD + Past Participle)

e.g - The play had started by the time we arrived at the theater.
(The earlier past action -- had started - is in the past perfect tense, while the later past action - arrived - is in the simple past tense.)

Otherwise, stick to simple tenses - as GMAT prefers simplicity.

e.g -

Incorrect - I think that ancient people HAD BELIEVED in many Gods.

Correct - I think that ancient people BELIEVED in many Gods.

In the above sentence the past perfect (had believed) is unnecessary because the sentence involves only one action in the past tense. Therefore, the simple past (believed) is correct.

Note the difference in meanings in the two sentences stated below

When I switched the TV on, the programme started. I was just in time.

When I switched the TV on, the programme had started. I missed the beginning.

Though ..... yet

1). When though is used with a verb in the subjunctive mood (expressing doubt, a condition contrary-to-fact, a wish, a concession) is followed by yet and not by but;

Though he might not have recognized me, yet it is rude of him.
Though she disallowed me, yet I will go to her.
Though he is poor, yet he is respected.

2). When though is used with a verb in indicative mood (expressing a fact or making a statement) a comma is used in place of yet.

Though he is my relation, I shall not spare him.
Though she is known to me, I shall not favour her.

Since vs For

Since / For

Since indicates a point in time.(since + starting point)

• I have lived in Bangalore since 1991.
• It's been raining since the beginning of the month.

For indicates the length of a period of time.(for + period of time)

• I have lived in Bangalore for ten years
• My mother will be in Delhi for the next ten days.

She'd been working there since a long time - Incorrect
She'd been working there for a long time - Correct

Few quick tips

1). There is -- considered wordy and may be frequently be omitted to create a more concise sentence.

2). When more is used in the comparative form of an adjective (more difficult) or adverb (more likely), it is followed by than.

3). They or it should not be used without definite antecedents. It must always be able to replace a noun.

e.g -- In that store they make a customer feel stupid.--- they is referring to whom? Here use of they is incorrect as there is no antecedent for they in this sentence so instead of they a proper noun should be used.

Note:In expressions of time and weather antecedent of it is not given.

e.g -- It is too hot today.

4). Subject form of pronoun always comes after ‘than’ or ‘as’.

e.g -- Peggy is smaller than I (am).

5). Because of is not same as caused by. An adverbial phrase beginning with because of answers the question "why" ?

e.g -- He is distrusted because of his deviousness. Here because of his deviousness is an adverbial phrase.

Why is he distrusted ? because of his deviousness.

6). Due to means caused by - Use due to only if it can be substituted by caused by.

7). Even if is used in conditional sentences to mean 'it doesn't matter if'.

e.g -- I will go on a tour of Europe next year even if none of you want to come with me.

8). We use a singular verb with the phrase the number of.

e.g -- The number of club members has increased this year.

9). We use a plural verb with the phrase a number of.

e.g -- A number of students were absent today.

10). Use of IN

i). IN + year / month / season

e.g -- in 1988 ; in september ; in winter ; in 21st century

ii). IN + a week or more

e.g -- in the easter holiday ; in the summer term

iii). IN + part of day

e.g -- in the morning ; in the evening

11). Use of ON

i). ON + day / date

e.g -- on wednesday ; on 15 April ; on that day

ii). ON + a single day

e.g -- on Easter monday ; on Christmas Day

iii). ON + day + part of day

e.g -- on Friday morning ; on Tuesday evening

12). Use of AT

i). AT + clock time / meal time

e.g -- at three o'clock ; at lunch (- time) ; at that time ; at the moment

ii). AT + two or three days

e.g -- at Easter / Christmas ; at the weekend (US : on the weekend)

Note - Exceptions - I woke up in the night (= in the middle of the night) ; It happened on Monday night ; I can't sleep at night (= when it is night)

13). We do not use in, on, or at before every, last, next, this, tomorrow and yesterday.

14). In time means 'early enough'

15). On time means at the right time , on schedule

I will keep updating this post .