文档介绍：(2)一般过去时:
These puters were made in Shanghai.
这些电子计算机是上海制造的。
When was the pleted?
这座大楼是什么时候建成的?
(3)一般将来时:
You won’t be allowed to take so much luggage with you.
不会让你带这么多行李。
What tools will be needed in the work?
工作中需要什么工具?
(4)现在进行时:
A new railway is being built.
一条新铁路正在修建。
The machine is being repaired in the factory.
机器正在工厂维修。
(5)现在完成时:
The aircraft has been redesigned.
这飞机已经重新设计。
The novel has been translated into many languages.
这本小说已被译成多种文字。
(6)过去进行时:
The case was being investigated.
这案件那时正在调查。
The roads were being widened.
路那时正在加宽。

(1)我们不知道或没有必要说明动作的执行者是谁:
Such books are written for children.
这种书是为儿童写的。
When will the road be opened to traffic?
这条路什么时候通车?
(2)动作的承受者是谈话的中心:
The song posed by a farmer.
这首歌曲是一位农民谱写的。
The lathe was designed by ourselves.
这个车床是我们自己设计的。
(3)出于礼貌措词圆通等方面考虑不愿说出动作的执行者是谁:
You are requested to give a performance.
请你给我们表演一个节目。
It is generally considered not advisable to act that way.
这样做一般认为是不妥当的。