词汇

grammar_british-grammar_before

释义

Before

Before is a preposition, an adverb and a conjunction. Before means earlier than the time or event mentioned:

Can you call me back before 5 pm, please?

I met her just before she left.

Warning:

In writing, when we refer back to something that we have already written, we use above not before:

As the graph above shows, the rate of inflation has risen by 15%.

Before as a preposition

We use before most commonly with noun phrases to refer to timed events:

I like to go for a run before breakfast.

You can check in online but you have to do it at least four hours before your flight.

We use before to refer to place, especially when it is seen as part of a journey or as part of a sequence of events in time:

Get off the bus just before Euston Station.

Just before the end of the poem, there is a line where the poet expresses his deepest fears.

Before, by, till, until

If you have to do something before a certain point in time, then when that point arrives, the action must already be completed:

I need to have the letter before Friday. (Friday is too late. I need it in advance of Friday.)

If you have to do something by a certain point in time, then that time is the last moment at which the action can be completed:

Can we finish this meeting by 5 pm. I have to get to the station by 5.30 pm. (5 pm is the latest that I want the meeting to finish and 5.30 pm is the latest that I can arrive at the station.)

If something is done or happens till or until a point in time, it happens over a duration of time, starting before that time and continuing up to that point:

[out-of-office auto-reply message on an email]

I’ll be out of the office until 17th May. I will reply to your email after that date. (I will be back on 17 May, but not before.)

Compare

I’ll be there until five o’clock.	I’ll be there up to five o’clock, but not after.
I’ll call you by five o’clock.	I may call you before five o’clock but I will call you no later than five o’clock.
I’ll be there before dinner.	I’ll be there earlier than dinner time.

Before as an adverb

Before often comes after nouns such as day, morning, night, week, month, year to refer to the previous day, morning, etc.:

Two people were ill at work yesterday and three people the day before!

A:
Did you graduate in 1989?

B:
No, actually, I finished collegethe year before.

Warning:

When we refer to a period of time that is completed and goes from a point in the past up to now, we use ago, not before:

A:
When was your birthday?

B:
It wasthree weeks ago.

Before as an adjunct

We use before to connect earlier events to the moment of speaking or to a point of time in the past:

I’m so looking forward to the trip. I haven’t been to Latin America before. (up to the moment of speaking)

I introduced Tom to Olivia last night. They hadn’t met before. (up to that point in the past)

Before as a conjunction

We use before as a subordinating conjunction. We commonly use before with the past simple tense. It suggests that the second event happened soon after the first one. The before clause, which indicates the second action, can be at the end or at the beginning of the sentence:

Before she left, she gave everyone a present.

She gave everyone a present before she left.

Before with present tenses

When we use before in clauses in the present tense, the clause can refer to the future:

Before I go to work, I jog for at least an hour.

Not: Before I will go to work …

Before with past tenses

We sometimes use before clauses in a variety of tenses to say that the action or event in the before clause did not or may not happen:

Before I had a chance to thank him, he’d gone.

You’re interrupting her before she has even spoken.

Before he had finished his training, he was sacked.

We should stop shopping now before we spend all our money.

Before with -ing

A non-finite clause with before + ing-form is more formal:

Before bringing the milk to the boil, add the egg. (more formal than Before you bring …)

Just before, immediately before

We can use adverbs such as just, immediately, shortly and long, and expressions involving words such as days, weeks, months, years in front of before:

We got home just before it rained.

The deadline for the essay was 5 pm. I got mine in shortly before five o’clock but Lily had hers in days before the deadline.

Beforehand

We can use beforehand as an alternative to before as an adverb, especially when the reference to time is less specific.

Spoken English:

Beforehand is more common in informal speaking than in writing:

I love singing but I always get so nervous beforehand.

In front of beforehand, we can put adverbs such as immediately, just and shortly, and other time expressions such as days, weeks, months, years:

Months beforehand, Dominic had bought five tickets for the concert.

Other uses of before

Before meaning ‘in front of’

We use before meaning ‘in front of’ in more formal contexts:

Brian was twenty years old. He had his whole life before him.

The Prime Minister went before the people to tell them that he was going to resign.

Before long meaning ‘after a short time’

Especially in writing, we use before long to mean ‘after a short time’:

They’ll marry before long, and then you’ll have more grandsons than you can count.

Before: typical errors

We use above not before when we refer back to something we have already written:

As stated above, there are four key findings from the study.

Not: As stated before, there are …

When we refer to a period of time that is completed and which goes from a point in the past up to now, we use ago, not before:

A:
When did you first meet?

B:
Ten yearsagowhen we were in college.

Not: Ten years before when …

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