Sorry I missed dinner, I had to / must work late. 2 You don't have to / mustn't do that. It's dangerous. 3 You shouldn't / don't have to stay up so late. You'll Ье tired in the morning. I couldn't / mustn't watch ТV for more then thirty minutes а day when I was а child. You mustn't / don't have to arrive еаrlу, but it's а good idea to do so. Excuse me, сап / mustn't I smoke hеrе?

1. does our institute train teachers? our institute doesn't train teachers. 2. did i enter university three years ago? i didn't enter university three years ago. 3. does she make good progress in english? she doesn't make good progress in english. 4. was moscow state teachers training institute founded in 1872? moscow state teachers training institute wasn't founded in 1872. 5. will they have seminars in history twice a week? they won't have seminars in history twice a week. 6. did she miss two lectures? she didn't miss two lectures. 7. do students take exams at the end of every term? students don't take exams at the end of every term. 8. did he fail in mathematics? he didn't fail in mathematics. 9. does she come from the north of our country? she doesn't come from the north of our country. 10. did she teach us french at school? she didn't teach us french at school.

1. Tom: Have__ you ever (been) to the USA ?
Angie: Yes, I (went) there last year actually.
2. Anna: Oh no! I (think) I ___have (lost) my keys! ___Have___ you (seen) them anywhere?
Benny: Well, they (were) by the phone earlier this morning. __Have you (looked) there?
3. Petra: Do___ you (know) where Antonio is?
Gerta: Yes, he (is) in his bedroom. He (is doing) his homework.
4. Amit: I am___ (going) for a walk. _Do___ you (want) to come?
Ajay: No, thanks. I (am expecting) a phone call.
5. Pittara: Have___ you (seen) Sasha recently?
Peach: Yes, this morning actually while I (was driving) to work. But, I ___have (not spoken) to him for weeks.
6. Pascal: ___Did you (see) him at the party last night?
Francois: Yes, but he (left) when we (arrived).