Question

定语从句中可以有被动语态吗？要怎么用？详细点

Answer 1

定语从句中可以有被动语态.是用主动还是被动取决于定语从句中主语与后面动词是主动还是被动关系。如：1.I know the girl who was hit by a car.
2.I know the girl who came to your room just now.
3.I know the girl (whom/who/that) you want to see.
第一句中who 指代的是the girl,即the girl was hit by a car。那个女孩被撞，所以用被动；
第二句中的who 也是指代the girl ，the girl 或who came to your room just now。who在定语从句中作came的主语，为主动，故用主动语态；
第三句中who 指代的也是the girl，但作主语的是you,即you want to see (whom/who/that)，即 you want to see the girl 。该说明的是，当关系代词在定语从句中充当宾语时可以被省略，括号为可以省略，斜杠为或者。
但要注意的是在中文中少数看似主动的词在英语中却要用被动，这跟英语单词的及物与不及物有关，也跟平时的积累有关。如：他坐在教室后面。（He is seated at the back.）他躲在门后。（He is hidden behind the door.）seat vt. (坐) hide vt. （躲藏）。vt.为及物，vi.为不及物

Answer 2

当然可以。定语从句使用被动语态，一般是在做出动作的人不重要或者不知道的情况下。例如：
I bought a computer that has once been used by others. 但是这种情况有往往可以将定语从句省略，使用过去分词做修饰语。I bought a book once used by others.

追问

如果关系代词换成which了还能省略吗？

追答

可以的。

追问

谢谢

追答

纠正一下上面的错误：I bought a computer that had once been used by others. 打错了。