1970 was the World Conservation(保护)Year. Everyone must know that the world is in danger.   16   is one example of the   17 .At one time there were 1,300 different kinds of trees and flowers in Holland(荷兰),but now only 866 remain(继续存在),   18 have been destroyed by modern man. We are changing the earth, the air and the water, and    19 that grows and lives. If we go on like this , we shall destroy ourselves.
What will happen in the future? Perhaps   20   is more important to ask “What must we do now?” The people who will be living in the world tomorrow are   21  young of today. A lot of them know that conservation is necessary. Many are helping to save   22 .
Now fifteen million young people in many countries are studying   23  and the country around him. In some countries they spend much time as “conservation volunteers.” They plant trees and help to   24  wild birds and animals.
But everyone,   25 young people, must work to save our world.

My brother is studying in ______ university in America; he wants to be ______ astronaut in the future.

1. A.
   a; a
2. B.
   a; an
3. C.
   an; a
4. D.
   an; an

He is a 16-year-old boy. __1__name is Alan Brown. Alan is __2__ American high school student. He lives at __3__ Road. Art and music __4__ his favourite subjects. He loves studying and also loves sports. He usually goes swimming three or four times every week. And he walks after supper every _5__. Cool water and clean air always make him happy. American students are quite different from __6__. On Saturdays, he often has parties __7__ his friends and they always enjoy themselves. On Sundays, he usually __8__ at home and watches TV.