All the students in Class One went to the cinema Li Ping. Why?—Because he had a stomachache.[ ]

Do you know _________ an “o” and _________ “u” in the word “computer”?

You’re dropped __________ “s” in the word “across”.－Oh, you are right, __________ letter “s” should be doubled like this “cross”.

This is the first book _______ my cousin bought me.

I don’t know when my son ________ back. When he_________ back, I’ll call you.