用方框中所给单词的适当形式填空，使短文正确、通顺（每词限用一次）。

Dear Dick,
How time flies! I have been back to school    two weeks. These days, I have   a lot about the population in China.
China has a population of 1.3 billion. It has reached about one   of the world’s population. About 80 percent of the people live in the   . It causes many difficulties. In less developed areas, not all the parents can offer    children a good education. Some children can’t go to school.
China has taken measures to    the population. China’s economy （经济）grows    faster and their living conditions have changed a lot.  of us have lived in bright and tall buildings. We have had ring roads and they are   enough. We have had more comfortable life.
 , the large population problem is still serious in China.
How about the population of your country? Can you tell me about it?
Yours,
Maria