Book 2 Unit 3 单元语法

Unit 3：现在完成时的被动语态
一、现在完成时被动语态的构成
1. 肯定形式：主语+has/ have been＋过去分词
The experiment has been done successfully.
这个实验做的很成功。
Many new buildings have been built since 2018.
自从2018年以来，许多新的大楼被建成。
2. 否定形式：主语+has/ have not been＋过去分词
The car has not been repaired yet.
这辆汽车还没有被修好。
These books have not been published.
这些书还没有被出版。
3. 疑问形式：Has/have+主语+been＋过去分词?
Has his bike been repaired?
他的自行车修好了吗？
Have the machines been used for a long time?
这机器使用很久了吗？
二、现在完成时被动语态的用法
1. 表示现在已经被完成的动作。常用的时间状语有：already, yet, just, never, ever, lately, recently, twice等，通常把副词放在助动词have或has的后面，有时候也可以放在句末。
Some flowers have already been watered by Li Ming.
一些花已经被李明浇了。
Has the Wi-Fi password been confirmed yet?
Wi-Fi密码被验证了吗？
Recently his novel has been translated into many foreign languages.
最近，他的小说被翻译成了好几种外语。
2. 表示一个被动动作从过去某个时间开始，持续到现在，并可能继续延续下去。常用的时间状语有：“for+一段时间”，“since+时间点/从句”，in/ for/over/during the last / past few years/months/weeks/days，ever since，so far，up to now，in recent years。
Much useful information about these planets has been collected since 1971.
自从1971年以来，关于这些行星的许多有用信息已经被收集。
Computer science has been taught in all universities for many years.
所有的大学开计算机课程已经很多年了。