The college students must study hard to      a good knowledge of advanced information technology.

. ---Isn’t it time you __________down to _________ your own things?---I’m sorry for the delay, Dad.

 I ______ laughing when my daughter made a face.

I am really worried about his grades in the coming test because of the little use he ______ of his spare time before it.

Mr. Thomas is ______ a teacher to us. We look on him as our friend.