10.(2013·四川高考)—Why are your eyes so red? You________have slept well last night.
—Yeah, I stayed up late writing a report.
A.can't B.mustn't
C.needn't D.won't
答案：A 考查情态动词的用法。句意：——你的眼为什么那么红?昨晚你肯定没睡好。——是的，我熬夜写一篇报道了。A项can't have done表示对过去的否定推测;B项表示“禁止，不允许”，不能用于对过去的推测;C项needn't have done表示过去不需要做某事(但却做了);D项不能用于对过去的推测。由句中的“so red”及时间状语“last night”提示，此处强调对过去发生动作的否定推测。
11.(2010·天津，9)Mark ________ have hurried. After driving at top speed, he arrived half an hour early.
A.needn't B.wouldn't
C.mustn't D.couldn't
答案：A 考查情态动词。句意：迈克本来不必那么匆忙的。这么高速驾驶之后，他提前半个小时到达了。根据后面的语境，提前半个小时到达，说明Mark本来不必那么匆忙，所以用needn't have done结构，表示“本来不必做某事而实际上做了”。
12.(2011·全国卷Ⅰ，32)They ________ have arrived at lunchtime but their flight was delayed.
A.will B.can
C.must D.should
答案：D 考查虚拟语气的用法。句意为：他们本该午饭时到达，但他们的航班推迟了。will have done将来可以完成;can have done可能做过……吗?表示对过去行为的怀疑，用于疑问句;must have done一定做过某事，表示对过去事情的肯定推测;should have done本来应该做某事，而实际没做。but their flight was delayed这样的结果，说明他们本来该到达却没有到达，因此选D。
13.(2012·湖南，21)We've had a good start, but next, more work needs________ to achieve the final success.
A.being done B.do
C.to be done D.to do
答案：C 考查情态动词的用法。need既可用作情态动词也可用作实义动词，在本句中用作实义动词故排除B项;need后可接动名词的主动式表被动含义，若选A项，则需改为doing，need doing=need to be done, 故C项正确。
14.(2012·新课标，30)I ________ use a clock to wake me up because at six o'clock each morning the train comes by my house.
A.couldn't B.mustn't
C.shouldn't D.needn't
答案：D 本题考查情态动词。句意：我没有必要用闹钟来叫醒自己因为每天早上六点火车从我家旁边经过。couldn't意为“不能，不可能”; mustn't意为“不允许，禁止”; shouldn't意为“不应该”; needn't意为“不必”，符合语境，故D项为正确选项。
15.(2010·湖南，23)You ________ buy a gift, but you can if you want to.
A.must B.mustn't
C.have to D.don't have to
答案：D 考查情态动词的用法。句意：你没有必要买礼物，但如果你想买的话，你也可以买。don't have to意为“没有必要”，符合语境。故选D。
