英語中有主動和被動兩種語態(tài).主動語態(tài)表示主語是動作的執(zhí)行者,被動語態(tài)表示主語是動作的承受者.只有及物動詞才有被動語態(tài).被動語態(tài)由“助動詞+及物動詞的過去分詞”構(gòu)成.被動語態(tài)的助動詞同樣有時態(tài)、人稱和數(shù)的變化.
1.A new computer was bought to me by my father yesterday.
2.The children are looked after very well by Mrs Zhang.
3.He was seen to come into the meeting-room.(這里注意一下：由于see是感官動詞,所以改為被動語態(tài)后要加to)
4.English is found very useful by us.
5.A lot of trees are planted by him.
后面的“by…”可加可不加,只要句子表示的是被動的意思就可以了.