By vs Until / Till

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I'll be back by 7 o'clock.

The deadline is 7 o'clock so I promise to be back anytime before 7, latest at 6:59.

I'll have gotten my degree in English by next year.

I expect to / promise to get my degree at a time between now and next year. In other words, I will be able to say I have my English degree when the next year comes.

Until / Till

Until and till are the same and interchangeable. Until a newer word and is usually preferred over till in writing and in speech. We use until to talk about something that will keep going on for a duration of time from a specific time to another.

Alan came yesterday. He will stay with us until the weekend.

Alan is with us at the moment and he is going to stay with us during the time from now to weekend.


Sometimes we can use both by and until in a sentence but their meanings differ from one another.

He has bad fever. He needs to be in bed until 10 o'clock.
He is already in bed and he needs to stay in bed.

He has bad fever. He needs to be in bed by 10 o'clock.
He is not in bed but for his goodness he needs to go to bed latest at 10 o'clock.

Also See: By vs Until Exercise 2

Quick Exercise

Choose by or until.

1. I will be taking care of my little brother Allan until by my parents come back.

2. I will have graduated from Harvard until by 2016.

3. I am so tired. I will sleep until by noon tomorrow.

4. Stay here and don't touch anything untilby I come back.

5. I need to turn in my homework untilby Monday.

6. You need to take me home untilby midnight or else she will get mad.

7. The party lasted until by sunrise.

8. We cannot trust them until by the war is over.

9. Do not play games until by late. Do your homework.

10. I need to pay the bill untilby August 5th.

Correctness =
Correct answers:

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