Before as an adverb
Before, as an adverb, means already, in the past and similar ideas.
- I have seen that film before.
Before can also mean at any time before the past moment that we are talking about. In this case a past perfect tense is used.
- She realized that she had seen him before.
We also use before after a time expression to count back from a past moment. A past perfect tense is normally used. Note that to count back from the present, we use ago, not before.
Before as a conjunction
- I will die before I surrender.
- Before I surrender, I will die. (Note the comma in the second structure.)
In a clause with before, we use a present tense to refer to the future.
- I will telephone you before I come. (NOT --- before I will come.)
To emphasise the idea of completion, we often use present and past perfect tenses in before-clauses.
- You cant go to bed before you have finished your homework.
In a formal style, we often use the structure before -ing.
- Please put out all lights before leaving the office.
Before as a preposition
The preposition before is normally used to refer to time.
- I must get home before nine oclock.
Note that before can refer to place in a few cases:
a) to talk about the order in which people or things come in queues, lists etc.
- Your name comes before mine on the list.
b) to mean in the presence of
- He was brought before the judge.
Back and Again
Bath and bathe
Beat and win
Because of, due to, owing to and on account of
Before and in front of
Begin and Start
Belong to, belong on and belong in
Below and under
Between and among
Between and during
Between and from
Big, large and great
Born and borne
Bring and take
But, though, in spite of, despite
By and with