Interviews were carried out ________ over the telephone，via e－mail or fax or face to face in four cities including Beijing，Shanghai，Guangzhou and Wuhan.

.Is there ______ rain in your area in spring? 

A good book is like a good friend. You cannot keep it          long.

 —Do you regret paying ten dollars for that book?—No, I would gladly have paid ________. 

Deserts, dry areas with _____ no vegetation, cover more than one-third of the Earth's land surface.