I tried knocking at the front door but nobody ___it

I tried knocking at the front door but nobody ___it I tried to wake up my life by knocking at the door,but she w Someone is knocking at the door,but who can____ be? I hear someone knocking at the door.的同义句 Listen!I hear someone knocking at the door. i seem to hear someone knocking at the door,knocking为什么要加ing 一道七年级英语题I saw someone knocking at the door.为什么用knocking,see i tried ____ (open ) the door ,but i failed . who is knocking at the door? 1.----Who is knocking at the door Listen!Who is knocking at the door? --Listen! Someone is knocking at the door.