it is time 是...的时候了。
这个结构有以下两种变形形式，所用虚拟语气形式都一样：it is high time / it is about time.
这三个结构后面加的句子谓语动词都用一般过去时来体现虚拟语气。
注意以下两种情况下should + 动词原形中should不能省略。
这里should表示一种语气，经常被翻译成“竟然”。
a. 四个动词：think, believe, expect, suspect.
它们的否定或者疑问形式后面加句子，句子谓语动词用：should + 动词原形，should不能省略。
I don't believe that he should be cheated. 我不相信他也会被骗。
b. it is a pity, it is a shame 真遗憾，it is strange 真怪
以上三个结构后面加的句子谓语动词用：should + 动词原形，should不能省略。
错综时态的虚拟语气
错综时态的虚拟语气即指主句和从句在表达是与什么时态的事实相反上并不一致(比如主句要表达与现在事实相反而从句要表达与过去事实相反)，这种情况要采用“对号入座”的方法来处理，即主从句结构分别采用与其表达时态对应的结构。
60. If I hadn’t stood under the ladder to catch you when you fell, you _A_ now.
A wouldn't be smiling B couldn't have smiled C won't smile D didn't smile
2. If you had studied the problem carefully yesterday, _C_.
A you won’t find any difficulty now B you would not have found any difficulty now
C you would not find any difficulty now D you have not found any difficulty now
3. He would be studying at the university now if he _C_ the entrance examination.
A passed B have passed C had passed D should have passed
16. It is a shame that he _B_ that poor little girl!
A deceived B should deceive C deceive D deceiving
18. Mrs. bliss kept the door and the windows shut lest the noise outside _D_ her son's sleep. [lest(以免，防备) 后面句子的谓语动词的形式都是：(should)+ 动词原形]
A would interfere with B had interfered with
C interfered with D should interfere with
21. The fifth generation computers, with artificial intelligence, _C_ and perfected now.
A) developed B have developed C are being developed D will have been developed
22. This ticket _C_ you to a free meal in our new restaurant.
A gives B grants C entitles D credits
A,B两项都要加双宾语，结构为：gives / grants sb. sth.
entitle sb. to sth. 使某人有权得到某物; credit A to B 相信A是由B造成的。
相信飞机失事是由飞行员错误造成的。 Credit the crash to the pilot's mistake.
crash 坠落，坠毁(专指飞机失事); collision 碰撞(强调两个物体碰撞，如火车、汽车等)。
we are sorry, very sorry, terribly sorry, awfully sorry.
23. You _D_ her in her office last Friday; she's been out of town for two weeks.
A needn't have seen B must have seen
C might have seen D can't have seen
24. That was so serious a matter that I had no choice but _D_ the police.
A called in B calling in C call in D to call in
have no choice but to do sth. 别无选择，只能做...
25. She was so _B_ in her job that she didn't hear anybody knocking at the door.
A attracted B absorbed C drawn D concentrated
be attracted by 被…所吸引; be absorbed in 全神贯注(专注)于做…
be drawn in 被诱骗(诱使)做... ; concentrate on 专注于。
I was simply drawn in. 我是被诱骗上钩的。
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