Until / By

Until and by are commonly confused by English learners.
Until refers to s “stop” time. “I will study until 8:00 pm.” (stop studying at 8:00 pm).
By refers to a “start” time. “I will be there by 9:00 am.” (start “being there” at 9:00 am).

I was awake until 10:00 pm. means I stopped being awake at 10:00 pm.
I was in bed by 10. means I began being in bed at 10:00 pm.

Examples of by and until
The New Matrix movie wont be on video until next year.
You can keep this CD until Thursday.
I will need the money by Friday.
You have to take the video back to the store by 7:00 pm.
The boss will be out of the office until Wednesday.
The Boss will be back by Wednesday.
You can stay out until 11:00 p.m.
I have to be home by 2:00am because my curfew is 2:00am.
I can stay out until 2:00 am.
You have until Tuesday to hand-in your homework.
You have to finish your homework by Tuesday.

Choose the best answer
A: What time were you out until last night?
B: Let’s see, my friends and I played pool until/by about 10 and then drank until/by 1:00 a.m. I didn’t feel too bad, though, because I was in bed until/by 1:30.

Ask your partner/ keypal these questions.
When you were 14 years old, what time did you usually have to be home by?
Answer eg.: I had to be home by 10:30 pm, how about yourself?

Until what age did you go to high school?
Answer eg.: I went to high school until I was 18 years old, you?

When did you have your first kiss?
Eg. I didn't have my first kiss until I was in high school.
Eg. I have my first kiss by the time I was 17 years old.