被动语态有 宾语么?
The classroom was cleaned (by us/students).
My homework has been finished.
Many trees were planted on the hill yesterday.
被动语态里面的动词,应该都是及物动词,既然是及物动词,一般后面都是要跟宾语的,
但在被动语态的句子中 看到,动词后面要么,不跟宾语,要么是跟一个by 短语（引出动作执行者）.
是不是被动语态中,尽管是及物动词,但后面不需要跟宾语啊?
我知道被动语态的主语,放在主动语态里面,是做动词的宾语.
这样的用法,是不是可以当作固定用法来记忆了.