Modals of Obligation and Necessity
1Công thức
must/have to/need to + base verb; had to (past); will have to/need to (future)2Giải thích
Must, have to, need to diễn tả sự bắt buộc và cần thiết: must thường là bắt buộc từ bản thân, have to là bắt buộc từ bên ngoài. Must không có dạng quá khứ hay nguyên mẫu nên dùng had to và have to; câu hỏi thường dùng Do I have to ...?
Must, have to and need to express obligation and necessity. Must often shows personal obligation and have to external obligation. Must has no past or infinitive, so had to and to have to are used.
Dấu hiệu: necessaryobligation
3Khi nào dùng
- Strong obligation (must/have to)
- Necessity (need to)
- Past obligation (had to)
- Future obligation (will have to)
4Quy tắc cần nhớ
- Must is rare in questions: use Do I have to / need to ...?
- Must cannot be used as an infinitive: I hate having to wait
- Past of must is had to; future is will have to or will need to
- Need can also take -ing in the sense of passive meaning: This shirt needs washing
5Ví dụ
Passengers must show their passports at the gate.
I had to wake up at five this morning.
You'll need to book a table in advance.
6Lỗi thường gặp
- I must to go now. (I must go / I have to go)
- Yesterday I must stay at home. (had to stay)
- Do I must wear a tie? (Do I have to wear a tie?)