问题
选择题
when you want to go into the room,you should _________the door.[ ]
A.knock on
B.knocking on
C.knocks at
D.to knock at
答案
答案:A
when you want to go into the room,you should _________the door.[ ]
A.knock on
B.knocking on
C.knocks at
D.to knock at
答案:A