阅读理解
People can cut down poplar trees(杨树)and use them for wood or paper. Their large roots help
reduce the loss of soil. Now, poplar trees are often used to prevent environment pollution.
The poplar trees are found in many places in the northern part ofthe world. They are fast growing
trees that need a lot of water.Different kinds of poplar trees are native to Asia, Europe and North
America.
Professor Richard-Meagher is now testing a poplar tree to take in mercury  (水银) through its roots. The tree then slowly releases(释放) the mercury into the air through its leaves. Mercurybuilds upin fish
and other living things,which is dangerous to people.Around a factory, Professor Meagher has planted one hundred and sixty poplars to remove the pollution. There is great interest in using plants to control harmful
things. And poplar trees are among the most studied.
1. What do people use poplar trees for?
A. Clothes or Wood.
B. Food or paper.
C. Wood or paper.
D. Clothes or food.
2. Where  are  poplar  trees from?
A. In the northern part of the world.
B. In the southern part of the world.
C. Asia, North Europe and America.
D. Asia, Europe and North America.
3. Poplar trees spread the mercury  into  the  air through         .
A. their large roots
B. their leaves
C. the soil
D. the water
4. What does the underlined part  "builds up" mean in Chinese?
A. 积累
B. 损失
C. 减轻
D. 穿过
5. What is the passage mainly about?
A. Growing poplar trees need a lot ofwater.
B. Poplar trees can clean the environment.
C. Mercury should be released.
D. Mercury is bad for people.

查看答案