by

I'll be back by 7 o'clock.

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

I'll have gotten my AWS certificate by next year.

explanation: I expect to / promise to get my certificate 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.

He has a [high temperature| bad fever| cold]. He needs to be in bed by 10 o'clock.

explanation: He is not in bed but for his health he needs to go to bed latest at 10 o'clock.

Ann: When will he be done?

Bob: He will be done by the end of the year.

Ann: When will this be done?

Bob: It will be done by 6 pm.

Ann: When will you [finish,exit] your probation period?

Bob: I will exit my [it,probation period] by the end of January.

Until / Till (UK)

Until and till are the same and interchangeable. Until is 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.

Adam came yesterday. He will stay with us until the end of the weekend. (He leaves on Sunday)

explanation: Adam is with us at the moment and he is going to stay with us during the time from now until Sunday. Sometimes we can use both by and until in a sentence but their meanings differ from one another.

Ann: How long will you be visiting your parents?

Bob: I'll be visiting my parents until the end of the month.

He has a bad fever. He needs to be in bed until 10 o'clock.

explanation: He is already in bed and he needs to stay in bed.

Ann: How long will you be working on this?

Bob: I will be working on it until I finish.

I will keep asking ___ you send my payment.

The store is open ___ 9 pm.

They said that they would finish the job ___ Friday.

I waited for him ___ 12 o’clock and then I went home.

I will be staying in this city ___ the end of this month.

I will be home ___ five o’clock.

___ the end of the party, everybody was drunk.

I will be in bed ___ the time you get home.

I will be ready ___ the time you arrive.

I will wait here ___ you come back.