In my pencil-box, _______ a pen, two pencils and three rulers.

— How much are the two pairs of trousers? — They are not expensive. I think one hundred dollars ______ enough.

This pair of shoes ________ mine. Those shoes __________ John’s.

We all feel it is Jack as well as his wife that_______for their son’s bad performance at school.

Nowadays signs prohibiting smoking       a common sight in restaurants, tea houses and shopping malls．