③（NMET2008福建）It is usually warm in my hometown in March, but it _____ be rather cold sometime.
A. must B. can C. should D. would
④（NMET2008辽宁）Peter ____ be really difficult at times even though he's a nice person in general.
A. shall B. should C. can D. must
【解析】①② 两个考题中can用于中表示否定的推测，意为：不可能，一定不会； ③④两个考题中can表示理论上的可能性，翻译为：有时候会……
【答案】① B ② A ③ B ④ C
（4）may （not） / might （not）表达一种不太把握的推测，意为"或许，可能";might的语气比may较婉转。例如：
① （NMET2008全国II） Liza ___ well not want to go on the trip --- she hates traveling.
A. will B. can C. must D. may
【解析】may well为固定搭配，意为：很可能，极有可能。
【答案】D
② （NMET2008四川） Although this ____ sound like a simple task, great care is needed.
A. must B. may C. shall D. should
【解析】这听起来或许是一项简单的任务，但却需要极大的细心。
【答案】B
③ （NMET2008重庆）-I can't find my purse anywhere.
-You __ have lost it while shopping.
A. may B. can C. should D. would
【解析】结合语境可知，回答者是在提醒对方：或许购物时把钱包丢了。
【答案】A