In some schools children who prefer to read books rather than ________ football become social outcasts (被抛弃者 ).

Senior members of the staff competed eagerly ________ the position of sales manager in the company.

It was three British sportsmen who ________ banned drugs.

Others argue that since the earth has endured a long string of ice ages in the last two millionto three million years, any warming is ________ to be temporary.

The problem ________ when the students refused to do their homework.

When he suddenly ________ up the subject of genetic engineering, there was an embarrassedsilence.

________ the concert had begun did we realize what a splendid show it was going to be.

The student found the novel _______. It provided him with so much information about the subject.

It is useful to science _______ the earth as an object in space.

________ with the size of the whole earth, the highest mountains do not seem high at all.