Monday, November 12, 2007

Until vs. As long as

Until can be used both as a preposition and as a conjunction. Until is used to express a point of time in the future

Until (preposition) -
  1. Up to the time of: We danced until dawn.
  2. Before (a specified time): She can't leave until Friday
Until (conjunction) -
  1. Up to the time that: We walked until it got dark.
  2. Before: You cannot leave until your work is finished.
  3. To the point or extent that: I talked until I was hoarse

As long as means that one thing will occur while another thing is still true

As long as (conjunction) -
  1. During the time that: I'll stay as long as you need me.
  2. Since: As long as you've offered, I accept.
  3. On the condition that: I will cooperate as long as I am notified on time.

Idiom

1. For the period of time that, as in You may keep the book as long as you want, that is, keep it for whatever time you wish to.
2. Also, so long as. Since, because, as in Please pick up some milk as long as you are going to the store, or So long as you're here, you might as well stay for dinner.
3. Also, so long as; just so. Provided that, as in As long as you don't expect it by tomorrow, I'll make the drawing, or So long as sales are greater than returns, the company will make a profit, or You may have another cookie, just so you don't take the last one.

Source: http://www.answers.com

1. In order to express a future idea. after as long as, we use a present tense.
e.g - As long as I live, I shall smoke no more cigarettes
2. Before a number, as long as can be used to suggest great length
e.g - The discussion can last as long as six hours