UNIT 119 By and until, By the time

A. By (+ a time) ='not later than':

* I posted the letter today, so they should receive it by Monday. (= on or before Monday, not later than Monday)

* We'd better hurry. We have to be at home by 5 o'clock. (=at or before 5 o'clock, not later than 5 o'clock)

* Where's Sue? She should be here by now. (=now or before now - so she should have arrived already)

You cannot use until with this meaning:

* Tell me by Friday whether or not you can come to the party. (not 'Tell me until Friday')

B. We use until (or till) to say bow long a situation continues:

* 'Shall we go now?' 'No, let's wait until (or till) it stops raining.'

* I couldn't get up this morning. I stayed in bed until half past ten.

* I couldn't get up this morning. I didn't get up until half past ten.

Compare until and by:

#1 until

Something continues until a time in the future:

* Fred will be away until Monday. (so he'll be back on Monday)

* I'll be working until 11. 30. (so I'll stop working at 11.30)

#2 by

Something happens by a time in the future:

* Fred will be back by Monday. (= he'll be back not later than Monday)

* I'll have finished my work by 11. 30. (I'll finish my work not later than 11. 30)

C. You can say 'by the time something happens'. Study these examples:

* It's not worth going shopping now. By the time we get to the shops, they will be closed. (= the shops will close between now and the time we get there)

* (from a letter) I'm flying to the United States this evening. So by the time you receive this letter, I'll be in New York. (= I will arrive in New York between now and the time you receive this letter)

* Hurry up! By the time we get to the cinema, the film will already have started.

You can say 'by the time something happened"(for the past):

* Jane's car broke down on the way to the party last night. By the time she arrived, most of the other guests had gone. (= it took her a long time to get to the party and most of the guests went home during this time)

* I had a lot of work to do yesterday evening. I was very tired by the time I finished. (= it took me a long time to do the work and I became more and more tired during this time)

* We went to the cinema last night. It took us a long time to find somewhere to park the car. By the time we got to the cinema, the film had already started.

Also by then or by that time:

* Jane finally arrived at the party at midnight, but by then (or by that time), most of the guests had gone.