关于英语主动变被动的小问题.
问题描述：
关于英语主动变被动的小问题.
They have to built many houses since last year.
变为被动后：
Houses have to been built since last year.
这么变对么?
be 为什么要改为 been?
没有be 变成 been
答
原句MS就有问题...时态好像不对
变被动不对 要用be 不能用been
原句估计应该是 They have built many houses since last year.
变被动后 Many houses have been built since last year.