请解答并解释

第10题

解题思路： 理解
解题过程：
选A
由第一句可知这些农民过去住在公路边，可知后面是对于过去的肯定推测，对于过去的肯定推测要用must have done的结构
列表对比看“情态动词+have done”结构的用法
“情态动词+have done”结构的用法是中学阶段的重要语法项目。为了便于同学们学习，现将这种结构的两种主要用法列表归纳如下：
一、表示对过去情况的推测或估计
结构
所用的句式
意义
must have done
肯定句
一定（已经）……
may/ might have done
肯定句
可能（已经）……
否定句
可能还没有……
can/ could have done
否定句
不可能（已经）……
疑问句
可能（已经）……了吗？
说明：1. might/ could有时并不是may/ can的过去式，而是表示一种委婉的语气或更小的可能性。
2. might have done有时可用于疑问句中，此时might就相当于can/ could。
二、表示对过去所发生的事情的遗憾或责备
结构
所用的句式
意义
should/ ought to have done
肯定句、否定句、疑问句
本来（不）应该……的
might/ could have done
肯定句
本来能够/可以……的
need have done
否定句
本不必要……的
说明：1. might have done有时可表示对过去发生事情的庆幸，意为“差点儿……”。如：
Didn’t you see that car nearly hit me? I might have been killed.
2. 要注意needn’t have done与didn’t need to do 意义的差别。如：
He needn’t have come. 他本没有必要来。（实际却来了）
He didn’t need to come. 他没有必要来。（实际也没来）
巩固练习
1. —Do you know where David is? I couldn’t find him anywhere.
—Well, he _________ have gone far, for his coat is still here.
A. shouldn’t B. mustn’t C. can’t D. wouldn’t
2. He ____________ you more help, even though he was busy.
A. might have given B. might not give
C. may not have given D. may give
3. There was plenty of time. She ___________.
A. mustn’t have hurried B. couldn’t have hurried
C. mustn’t hurry D. needn’t have hurried
4. —Tom graduated from college at a very young age.
—Oh, he ______ have been a very smart boy then.
A. could B. should C. might D. must
5. My English-Chinese dictionary has disappeared. Who ______ have taken it?
A. should B. must C. could D. shall
6. I really worried about you. You ________ home without a word.
A. mustn’t leave B. shouldn’t have left
C. couldn’t have left D. needn’t leave
Key: 1~6 CADDCB
最终答案：略