by / before

Question

What is difference? This was our last-minute shopping by / before New Year.Are they same in meaning? If not, how do we know?

Mister Micawber · Accepted Answer

'By' is not used there.

Vincent Teo · Answer

but the meaning of "by" is before, right?

Mister Micawber · Answer

It doesn't work here.

CalifJim · Answer

Vincent Teobut the meaning of "by" is before, right?

As with many 'meaning equivalents' in English, the relationship is not symmetrical.

To understand an English sentence with "by" (with times), you can often substitute "before" to get the same general meaning.
However, you can't substitute "by" for "before" in any sentence you want and expect it to have the same meaning.

You might say, in this limited context, that "by" means "before", but "before" does not mean "by".

CJ

Vincent Teo · Answer

Thanks, but how do we know or how to differentiate "before" and "by"?

CalifJim · Answer

Vincent TeoThanks, but how do we know or how to differentiate "before" and "by"?

'by' is used for time limits, deadlines. There is an implicit race with the clock. Something has to be done by a certain time.

I have to be there by 9 o'clock.
They must pay their gas bill by April 4.
She has to finish her homework by tomorrow.

The idea of racing with time is less obvious in some cases. 'by the time' can be used with clauses.

The train had already left the station by the time I got there.

If you just did something without any obligation or desire to do it within a certain period of time, use 'before'.

I got my hair cut before I went to lunch. (No obligation to get the haircut within a certain period of time. Just two events.)

CJ

by / before

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