1 . Many lessons are now available online, from ___________students can choose for free. (用适当的词填空)

2 . In our school there are 50 students, half of __________ wear glasses. （用适当的词填空）

3 . The science of medicine, _________which we owe a great deal, is perhaps the most important of all the branches of science. (用适当的词填空)

4 . ________ is known to all, good friends ________ happiness and value to life.

A．It; add

B．As; add

C．It; add up

D．As; add to

5 . The number of smokers, _________ is reported, has dropped by 17 percent in just one year. （用适当的词填空）

6 . On Sundays there were a lot of children playing in the park, ________ parents sat together joking.

A．their

B．whose

C．which

D．that

7 . He wrote many children’s books, nearly half of________ were published in the 1990s. （用适当的词填空）

8 . In 1963 the UN set up the World Food Program, one of_________purposes is to relieve worldwide starvation.（用适当的词填空）

9 . You won’t apologize to me, in __________ case, I have no more to say.

10 . Dr. Rowan, ________ secretary resigned (辞职) two weeks ago, has had to do all his own typing.（用适当的词填空）