I.

1. learns - doesn't seem (usually: thường xuyên => dấu hiệu thì hiện tại đơn)

2. is waiting - want (câu này xác định thì dựa vào ngữ cảnh)

3. were dancing - broke - stole (hành động đang diễn ra trong quá khứ - chia quá khứ tiếp diễn, hành động cắt ngang - chia quá khứ đơn)

4. had (this afternoon: chiều nay => lúc nói đã qua buổi chiều rồi => quá khứ đơn)

II.

1. to go (would like sb to V: muốn ai đó làm gì) - go (make sb + V_nguyên thể: bắt ai làm gì)

2. look (had better + V nguyên thể = should: nên)

3. go (let sb + V_nguyên thể: để / cho ai làm gì) - promise - not to tell 

4. quietly (adv, đứng sau V là adv)

III.

1. I was too tired to walk further. 

2. This coffee isn't strong enough to keep us awake.

Bicycles mustn't be left in the hall.

3. The work is being done a lot by students.

4. He apologized for being late because his bus had broken down.

5. Andrew wanted to know the reason why Betty didn't come to his birthday party the night before.

6. If you don't listen carefully, you will not understand the lesson.

7. The man who/whom you met at the party last night is a famous actor.