I cannot understand why Steven bought so many watches but never wears 　　　 of them.

Our factory has been developing rapidly these days． This year’s production is five times ______ it was ten years ago．

 —The phone is ringing —Who could            be? It is already midnight .

Use your head. nothing taught by others can have the same effect on you as ________learned by yourself．

---Why don't you go to the lecture-room and listen to the talk? 　---I hear there isn't ________in it.