问题描述：
when you leave the room,make sure_____the door.
a)of locking b)you lock c)foryou to lock d)to lock
选哪个?为什么?
a)of locking b)you lock c)foryou to lock d)to lock
选哪个?为什么?
问题解答：
我来补答展开全文阅读