How do we use the prepositions By and Until in English when they refer to time? Take a look at the following examples:
Write the report until 5 pm.
Write the report by 5 pm.
Write the report until 5 pm means “Start writing the report now, continue writing it until 5 pm, then stop writing it regardless of whether it is finished or not.”
Write the report by 5 pm means “Make sure that at 5 pm the report is written and finished”. This example makes more sense than the first one.
As a preposition of time by means on or before.
E.g. We will send you the documents by tomorrow.
- Use “by” when you refer to a deadline.
Until means up to a particular time.
E.g. We have until tomorrow to send out the documents.
- Use “until” when you refer to the period of time before a deadline.
By is used to describe an action or event that happens on or before a particular moment.
E.g. We expect to know the judgment by the end of June.
Until is used to describe a state or situation in the period of time up to a particular moment.
E.g. The court proceedings are expected to last until June.
You may think of until as referring to the moment a state or situation changes.
E.g. Comments on the draft may be submitted until March 2nd.
Here are some more examples:
- I can do it by 3 pm.
Now → do it and finish it → 3 pm (it will be finished)
- I can do it until 3 pm.
Now → do it → 3 pm (I’ll stop even if I haven’t finished)
- I can’t do it by 3 pm.
Now → do it / not do it → 3 pm (either way it won’t be finished)
- I can’t do it until 3 pm.
Now → can’t do it → 3 pm (I’ll start)
Fill in the sentences with by or until:
- I need to do the laundry ______ 7pm.
- They have ______ March 3rd to move out of their apartment.
- We can play ________ he comes home.
- My friends are supposed to come _______ next week.