Unit 1 Festivals around the world

any man with a little sense can see that he is wrong.
（2）may i / we …？這一類疑問句的肯定回答為yes, please.或certainly；否定回答為please don’t.或no, you mustn’t. 例如：
“may we leave now?” “no, you mustn’t. you haven’t finished your home work yet.”
4. can 和 be able to
can 與 be able to 都可以表示能力，但兩者在用法上有點差異：can (could)表示主觀能力，不表示意愿，它的將來時用will be able to; be able to表示主觀意愿，強調要克服困難去做某事。例如：
1）my grandma is over seventy, but she can still read without glasses.
2）he is able to give up his bad habits.
5. must 和 have to
must 和 have to 都可以表示“必須”，但有幾點區別：
（1）must 強調“內在的職責”、“義務”，而have to 強調“外界壓力”、“不得已而為之”。
（2）have to可用于多種時態，而must一般用于現在時，其過去時與將來時分別由had to與shall / will have to代替。
（3）在回答must引起的問題時，如果是否定的答復，不能用mustn’t，而要用needn’t或don’t have to，因為mustn’t是“一定不要”、“一定不能”的意思。例如：
1）you must come to the classroom before eight.
2）it is raining hard outside, but i have to leave now.
3）“must we do it now?” “no, you needn’t.”
6. used to +do, be used to +doing和be used to +do
（1）used to +v意為“過去常常”，“過去一直”；be used to +v-ing / n（名詞）意為“習慣于”；be used to +v意為“被用來（做某事）”。
（2）used to只表示過去，而be used to +v-ing / n可表示現在、過去或將來。例如：
1）he used to smoke. now he doesn’t.
2）he’s quite used to hard work / working hard.
3）the knife is used to cut bread.
7.用作情態動詞的其他短語
would rather, would sooner, would (just) as soon, had rather, had better, had sooner, can not but, may (just) as well等可用作情態動詞。例如：
1）the soldier would sooner die than surrender.
2）the brave soldier would as soon die as yield to such an enemy.
3）i’d rather walk than take a bus.
4）if you don’t like to swim, you may just as well stay at home.
注：這些短語后一般直接跟動詞原形.would (had) rather, would (had) sooner, would (just) as soon后可跟that 引導的從句，that 常省去，從句要用虛擬語氣。對現在和將來的假設用過去時，對過去的假設用過去完成時。例如：
1）i would rather you came on sunday.
2）i would sooner you hadn’t asked