题目内容
动词填空。
Don't enter the room without ________ (knock) on the door.
动词填空
I don't know how ________(say)it in English.
I don't know what ________(happen)to the girl.She looks so sad at the moment.
Don't make any noise. I hear someone ________ (knock) at the door.
Don't give up ________ (study) English, it's so useful.