Question

几道选择题，对选择理由请稍作解释

There is a police car in front of his house,what do you suppose______to him?
A. happens B.has happened

The water will be further polluted unless some firm measures______
A. will be taken B.are taken C. were taken D.had been taken

No permission_____for anybody to enter the building.
A.has been given B.was given c. will give D. is giving

We______the star for an hour,but he ______ yet.
A. have waited for;hasn't come B.have waited for;doesn't come C.have been waited for;doesn't come D.have been waiting for;doesn't come
最后一题的最后一个选项应该是 D.have been waiting for;hasn't come

Answer 1

1、选B There is a police car in front of his house是发生的事情对现在造成的影响，由于事情已经发生了，所以用现在完成时。故选B
2、选B unless 是“除非”的意思，引导的是条件状语从句，应该是主将从现，主句的将来时已由will确定，从句用一般现在时。故选B
3、选B 根据句意可知，句子的时态为过去式故选B
4、选A for an hour是一段时间，所以所用的动词应为延续性动词，yet表示这句话的时态为现在完成时。故选A

Answer 2

B.has happened
现在完成时，强调他发生了什么

B.are taken
unless引导的句子中，主句用一般将来时，从句用一般现在时表将来

A.has been given
强调到目前为止，没有。。。

D.have been waiting for;hasn't come
have been waiting 现在完成进行时，表示过去一直在等，到现在，有可能还要继续等下去

追问

再仔细看一下最后面的一个题，我怎么没看到两个完成时同时出现在一个句子里面的情况啊？
是否其中一句应该改为一般现在时呢？

追答

有吧，我以前也见过这类题的，前面用现在完成进行时，表示已经一直在等，有可能还需要继续等（因为他还没有来），而后面有个yet更是典型的用完成时，he hasn't come yet 他到目前为止还没有来。

我们已经在这等了一个多小时了，但是还到现在还没有来。 逻辑上还算正常的吧
还有这题目在网上搜一下，有类似的题目滴。。http://zhidao.baidu.com/question/38934928.html?an=0&si=2

Answer 3

1B 2B 3C 4D