英语在线主动改被动 we don't allow students to smoke. we built a bridg

如下
1.Students are not allowed to smoke.
2.A bridge was built last year.
3.A letter will be written by me to my mother.
4.He was often told not to make a noise.
5.Two books can be lend from the library each time.
6.A computer will be bought for him by his parents.

1、Students aren't allowed to smoke.
2、A bridge was built by us last year.
3、A letter will be written to my mother by me.
4、He is often told not to make a noise.
5、2 books can be borrowed from the library each time.
6、A computer will be bought for him by his parents.

请参考。