15．– How cold it is! I wonder how grass survive under such heavy snow．
--Don’t worry．There is a lot of air in loose snow which _______．

we can avoid _________ with rest and a balanced diet.

Almost all the students were having classes when the earthquake _________.

He_________ to paint the whole house but finished only the front . 

“How much do you ____ for repairing such a pair of shoes?”“Two dollars, sir.”

“We have faith with people” means “we should ____ people, our families, our teachers, our friends and our teachers.”

Joining the firm as a clerk, he got rapid promotion , and_______as a manager.

He telephoned the travel agency to_______three air tickets to London.

The experiment has_________ the possibility of the existence of any life on that planet, but it does not mean there is no life on other planets.

Thousands of foreigners were______ to  the Shanghai World Expo the day it opened.