外研版高中英語必修三《The world of science》PPT下載(第2課時)，共12頁。
現(xiàn)在完成時的被動語態(tài)的用法
1．表示被動的動作在說話之前已經完成，強調過去的動作對現(xiàn)在造成的影響或產生的結果，通常與already，yet，never，recently等副詞及時間狀語so far，by now，up till/to now，since等連用。
The databasehas already been updated.
數據庫已經被更新了。(現(xiàn)在可以使用新的數據庫了)
2．表示一個被動的動作或狀態(tài)從過去開始一直持續(xù)到現(xiàn)在，并可能繼續(xù)持續(xù)下去，常與for或since等引出的時間狀語(從句)連用，或用于howlong引出的句子中。
The machine has been repaired for two hours.
這臺機器已經被修了兩個小時了。(可能還會繼續(xù)被修)
3．用在條件狀語從句中，表示將來某時已經完成的動作。
You shouldn’t leave school beforeyour homework has been finished.
在你的作業(yè)沒完成之前你不應該離開學校。
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.
... ... ...
關鍵詞：The world of science PPT課件免費下載，.PPT格式；
