Though great progress has been made in science these years,there

1．________

are still many people living in poor conditions．They make their lives

2．________

by collecting and selling used thing．Their children cannot go to school

3．________

because they have not enough money to send their children to there．

4．________

Why you think so many people still suffer from poverty now?

5．________

The answer lies on tile population wxplosion．A president

6．________

of a developing country once said:“It is us who are to blame

7．________

the poverty because we used to produce' child without limit．

8．________

Although this few words sound simple enough,they have

9．________

clear pointed out one of the causes of the population explosion．

10．________