几道关于情态动词的英语题目：

题目

几道关于情态动词的英语题目：
1.Would you be so kind as to keep an eye on my house while I am away?
(so+adj.+as to do sth怎么理解,这里的Would 能不能改为Can或Could,原因）
2.Should the pain return,take one of these pills.怎么理解这个should
3.He ordered that Tom should leave th house at once.这里的should可以换成must吗?原因.
4.There is a knock at the door.Who can it be?这里的can能改成may?原因.
5.-Can you go swimming wiht us this afternoon?
-Sorry,I can't.I ____ take care of my little sister at home because my mother is ill.
A.can B.may C.would D.have to
6.-Mr.Smith must have been to your home this morning.
-No,he ______,because he didn't know my address.
A.couldn't B.can't C.mustn't D.may not

答案

1.so+adj.+as to do sth 做结果状语 would表示委婉的请求,could也有这种用法.
2.should表示一种条件,可译为：万一
3.动词order后宾语从句用虚拟语气,从句谓语用should+动词原形或直接用动词原形.
4.can be 常用于否定句或疑问句中表示不太肯定的猜测；may be 一般用于肯定句中表示不太肯定的猜测.
5.D have to 表示客观上的必须.
6.A 上句时间为 this morning,视为过去时间,could 这里作为can 的过去式对待.