外研版（2019）英语必修第三册《The world of science》PPT下载(第2课时)
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外研版高中英语必修三《The world of science》PPT下载(第2课时)，共12页。
现在完成时的被动语态的用法
1．表示被动的动作在说话之前已经完成，强调过去的动作对现在造成的影响或产生的结果，通常与already，yet，never，recently等副词及时间状语so far，by now，up till/to now，since等连用。
The databasehas already been updated.
数据库已经被更新了。(现在可以使用新的数据库了)
2．表示一个被动的动作或状态从过去开始一直持续到现在，并可能继续持续下去，常与for或since等引出的时间状语(从句)连用，或用于howlong引出的句子中。
The machine has been repaired for two hours.
这台机器已经被修了两个小时了。(可能还会继续被修)
3．用在条件状语从句中，表示将来某时已经完成的动作。
You shouldn’t leave school beforeyour homework has been finished.
在你的作业没完成之前你不应该离开学校。
Practice
Rewrite the underlined sentences in the passage using the present perfect passive.
① It has already affected many things in our lives.
② Some restaurants in London have served 3D-printed hamburgers to customers.
③ The most significance success that people have achieved to date is in medicine.
④ They have made human body parts, including a beating heart, with 3D printing technology.
⑤ People have given a new 3D-printed shell to a turtle injured in a forest fire.
Homework
Rewrite the following sentences with the present perfevt passive.
1. You can see that they have not painted thehouse for years.
2.It is said that two thieves have broken intothe house .
3. Have people criticized his views ?
4. He has not taken away the two books.
5. Where have you repaired the mobile phone?
6. The company has brought down the price ofthe colour TV set again .
7. My parents gave me a toy at Christmas.
8. Someone saw a stranger walk into thebuilding.
9. They saw the boy smoking a cigarette.
10. The boss forced the workers to work day andnight.
... ... ...
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