【正文】
You must close the windows. The windows must be closed. The viewer can touch the objects. The objects can be touched. (We can use modal verbs in the passive voice to talk about ability, possibility, duty, permission, etc.) Modal verb +be done 時(shí)態(tài) 主動(dòng)語(yǔ)態(tài) 被動(dòng)語(yǔ)態(tài) (be+過(guò)去分詞 ) 一般現(xiàn)在時(shí) see / sees am(is,are)+seen 一般過(guò)去時(shí) saw was(were)+seen 一般將來(lái)時(shí) will (shall) +see will(shall)+be+seen 過(guò)去將來(lái)時(shí) would(should)+see would(should)+be+seen 現(xiàn)在進(jìn)行時(shí) am(is,are)+seeing am(is,are)+being+seen 過(guò)去進(jìn)行時(shí) was(were)+seeing was(were)+being+seen 現(xiàn)在完成時(shí) have(has)+seen have(has)+been+seen 過(guò)去完成時(shí) had+seen had+been+seen 含情態(tài)動(dòng)詞 情態(tài)動(dòng)詞 +see 情態(tài)動(dòng)詞 +be+seen 以 see為例,比較主動(dòng)語(yǔ)和態(tài)被動(dòng)語(yǔ)態(tài)的結(jié)構(gòu)形式 3).Sharon will bring some books. A letter is being written by you. 2).You are writing a letter. 1).The cat plays the ball. Have a try: Change the following sentences into the passive voice. The ball is played by the cat. Some books will be brought by Sharon. Some pictures had been painted by us before you came. 6).We had painted some pictures before you came. Her homework was being done by Jane. 5).Jane was doing her homework. A bag was brought for me by my mum. 4). My mum bought a bag for me. Practice: Fill in the blanks with the right form of the words given: 1). I _________ (give) a new book by my father on my birthday. 2). English