備戰(zhàn)2019屆高考英語（通用版）一輪復(fù)習(xí)專題12 情態(tài)動詞
—you ______ have my computer if you don’t take care of it.
a.shan’t
b.might not
c.needn’t
d.shouldn’t
解析:后者意為如果你不愛惜電腦的話，就不允許你用。shall用于二、三人稱表示允諾。如：
you shall have a copy if the book is published.
書一出來你就會得到一本。
you shall get the answer right this afternoon.
今天下午你就可以得到答復(fù)。
the enemy shall be wiped out.敵人一定會被消滅。
答案：a
【示例4】i often see lights in that empty house. do you think i ______ report it to the police?
a.should
b.may
c.will
d.can
解析:空房子常亮著燈，不正常，所以應(yīng)該報告警方。準(zhǔn)確掌握各情態(tài)動詞的基本意義且緊密結(jié)合上下文才能正確地使用，因而二者不可或缺。
答案：a
【示例5】children under 12 years of age in that country ______ be under adult supervision when in a public library.
a.must
b.may
c.can
d.need
解析:那個國家里12歲以下的孩子到公共圖書館去須由大人監(jiān)護(hù)。這是法律條文或圖書館的管理規(guī)定，人人必須遵守。
答案：a
【示例6】—catherine, i have cleaned the room for you.
—thanks. you ______ it. i could manage it myself.
a.needn’t do
b.needn’t have done
c.mustn’t do
d.shouldn’t have done
解析:needn’t have done表示“過去本來沒有必要做而做了”，而shouldn’t have done表示“過去本來不應(yīng)該做而做了”。
答案：b
思維升級
“情態(tài)動詞＋have＋過去分詞 ”結(jié)構(gòu)是情態(tài)動詞專項考查的難點和重點，記住以下最常考查的結(jié)構(gòu)：
（1）must have done “過去一定做了某事”
（2）can’t/couldn’t have done “過去不可能做了某事”
（3）may/might have done “過去可能做了某事”
（4）needn’t have done “過去本來沒有必要做而做了某事”
（5）could have done “過去本來能夠做某事而沒有做”
（6）should/ought to have done “過去本來應(yīng)該做某事而沒有做”
（7）shouldn’t/oughtn’t to have done “過去本來不應(yīng)該做某事而做了”
【示例7】i have lost one of my gloves. i _____ it somewhere.
a.must drop
b.must have dropped
c.must be dropping
d.must have been dropped
解析:must have done表示“過去一定做了某事”。句意為：我丟了一只手套，我肯定是掉在什么地方了。
答案：b
【高考鏈接】
1.（XX高考英語江蘇卷）---i haven’t got the reference book yet, but i’ll have a test on the subject next month.
---don’t worry. you______ have it by friday.
a. could b. shall c. must d. may
【答案】b
【解析】本題考察情態(tài)動詞的用法。shall在第二人稱中表示允諾，還可表示強制，命令，威脅，警告等，還有在法律條文中的要求和規(guī)定。
2.（XX高考英語上海春季卷）it is important to know about the cultural differences that cause problems.