Подчеркните правильный вариант модального глагола в следующих предложениях:
1. Must/Can I have a biscuit please, Mum?
2. May/can you see anything in this inky darkness?
3. He must/can work systematically if he wants to know French well.
4. Must/May I borrow these files for a moment, sir.
5. Have to/may I come in?
6. He can/must not speak English yet.
7. I will be able to/can pass my exam.