As a Chinese proverb goes， a heavy snow _____ a good harvest year.

More have been learned since 1945 about chemical changes in the body than in all human history before _____ time.

My own problems seem insignificant _____ those of others.

He （ ） me to give up the holidays in Spain next month.

It is essential that all these figures （ ） twice.

Most computer users are （ ） threat from computer viruses．

Could you please _____ why you can’t come to attend the meeting?

Each car sold in this specialized shop comes with a one-year （ ）.

The travelers are going to Taiwan, （ ） they plan to stay for two or three days.

The father went to the door in （ ） to a knock from outside.

There is nothing new about women （ ） their careers to look after children.

Many teenagers feel no difficulty （ ） computer.