Unit 4 A charity show-

1. 現在完成時的被動語態有兩個助動詞，即 have/has和been，兩者缺一不可。
2. 注意與一般過去時的被動語態的區別。一般過去時的被動語態表示一個被動的動作發生在過去某個時候，其結果對現在沒有影響；而現在完成時的被動語態的動作或狀態盡管發生在過去，但側重說明該動作或狀態對現在造成的影響和結果。例如：
the house was built last year. 這房子是去年建造的。
the house has been built. 這房子已經建好了。
3. 由finish，buy，start，begin，post，return，borrow，join，marry，open等詞構成的現在完成時的被動語態不能與表示一段時間的狀語如for four days，how long等連用，而要改換動詞或時態。例如：
譯：這本書買了多久了？
誤：how long has this book been bought？
正：how long ago was this book bought？
但這類動詞的否定式可表示動作的持續過程，具有延續性，因而可與since或for引導的時間段連用。例如：
no books have been bought since last week. 自上周以來，沒有人來買過書。
4. 短語動詞是一個不可分割的整體，在被動結構中要保持完整性，不可省略短語動詞中的介詞或副詞。例如：
the old man has been well looked after. 這位老人一直受到很好的照顧。
 
【典型例題】
(  ) 1. now these magazines___ in the library for a long time.
a. have kept   b. are keeping   c. have been keeping  d. have been kept
(  ) 2. the pot ___ for ___ hot water.
a. used; keeping       b. was used; keeping 
c. is used; to keep      d. are used; keep
(  ) 3. tea ___ in the south of china for hundreds of years.
a. has been grown      b. is grown 
c. were grown       d. will be grown
(  ) 4. the bridges___ since two years ago.
a. have been built b. have built   c. were built    d. was built
(  ) 5. the meeting ______ since 5 o’ clock.
a. has had     b. had     c. have been had    d. has been had
【答案】
dbaac
 
語法三：含有情態動詞（can, may must, should, ought to）的被動語態
1、this bike can be repaired.
2、the tree must be put straight in the hole.
3、the classroom should be cleaned every day.
含有情態動詞的主動句變成被動句時，由“情態動詞＋be＋過去分詞”構成，原來帶to的情態動詞變成被動語態后“to”仍要保留。
歌訣是：情態動詞變被動，情態加be加“過分”，原來帶to要保留。例如：
we can repair this watch in two days.
—this watch can be repaired in two days.
you ought to take it away.
—it ought to be taken away.
they should do it at once.
—it should be done at once
肯定式：can/may/must/should/ought to be done
否定式：can’t/may not/mustn’t/shouldn’t/ought not to be done