問句：Need you…? / Must you…?
肯定回答：Yes, I must.
否定回答：No, I needn't/don't have to.
典型例題
1）---Could I borrow your dictionary?
---Yes, of course, you____.
A. might B. will C. can D. should
答案C.could表示委婉的語氣，并不為時態(tài)。答語中of course，表示肯定的語氣，允許某人做某事時，用can和 may來表達，不能用could或might。復習： will 與you連用，用來提出要求或下命令。should與you 連用，用來提出勸告。
2）---Shall I tell John about it?
---No, you ___. I've told him already.
A. needn't B. wouldn't C. mustn't D. shouldn't
答案A。needn't 不必，不用。 wouldn't 將不, 不會的。 mustn't 禁止、不能。 shouldn't 不應該。本題為不需要，不必的意思，應用needn't。
3）---Don't forget to come to my birthday party tomorrow.
---______.
A. I don't B. I won't C. I can't D. I haven't
答案B. will既可當作情態(tài)動詞，表請求、建議、也可作為實義動詞表"意愿、意志、決心"，本題表示決心，選B。
