Do you know something about tree rings? Do you know they can tell us what the weather was like, sometimes even hundreds of years ago?
A tree will grow well in a climate with lots of sunshine and rainfall. And little sunshine or rainfall will limit the growth of trees by studying the tree rings. For example, to find out the weather of ten years ago, count the rings of a tree from the outside to the inside. If the tenth ring is far from the eleventh ring, then we’re sure that it was sunny and rainy most of that year. If it is near to the eleventh ring, then the climate that year was bad.
Tree rings are important not only for studying the history of weather but also for studying the history of man. Many centuries ago, there lived a lot of people at a place in New Mexico. But now you can find only sand there－no trees and no people. What happened?
A scientist studied the rings of dead trees there. He found that the people had to leave because they had cut down all the trees to make fires and buildings. As all the trees had gone, the people there had to move.

Tree rings can tell ______ according to the passage.
A. whether a tree was strong or not.
B. whether the climate was good or not
C. how tall trees used to be.
If you want to find out the weather of twenty years ago, you should study ________.
A. the twentieth ring
B. the tenth ring
C. the twenty-second ring
What does the underline word “limit” mean?
A. 证实                        B. 限制                           C. 促进
Which of the following is NOT TRUE?
A. Trees can’t grow well in a climate with little sunshine and rainfall.
B. Tree rings grow far from each other in a bad climate.
C. The people left the place in New Mexico because the land became sand.
The passage mainly tells us  ________ .
A. how climate affects the growing of trees
B. the importance of the trees
C Tree rings can help us study the history of weather and man.