How much rain has fallen on the earth in the past? Man has not always kept weather records. Because scientists need a way to learn about past rainfall, they study the tree rings.
A tree’s trunk (树干) keeps growing year by year. Under its bark (树皮), a tree adds a layer of new wood each year it lives. If you look at a tree stump, you can see the layers. They are called annual ring (年轮).
On some trees, all of the rings are of the same width. But the ponderosa(美国黄松) that grows in the American southwest have rings in different withes. The soil in he southwest is dry. The pines depend on rainfall for water. In a year of good rainfall, they form wide rings. In a dry year, they form narrow ones.
Scientists do not have to cut down a pine to study its rings. With a special tool, they remove a narrow piece of wood from the trunk without harming the tree. Then they look at the width of each ring to see how much rain fell in the year it formed.
Some pines are hundreds of years old and have hundreds of rings. These rings are from an annual record o0f past rainfall in the southwest.
1.We could infer from the passage that ______.
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A．a tree grows faster when it has a lot of water |
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B．scientists cut down trees to study tree rings |
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C．pine trees form rings of he same width every year |
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D．the ponderosa grows in he southeast |
2.A tree grows a new layer of wood _____.
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A．each week |
B．whenever it rains |
C．every year |
D．every season |
3.On the whole, the passage is about _____.
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A．why the tree trunks grow bigger |
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B．why scientists study tree rings |
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C．trees that lived hundreds of years ago |
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D．the ponderosa in the US |
4.The scientists _____ to know how much rain fell in a certain area in the past.
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A．climbed up the tree |
B．moved the pine tree |
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C．removed a piece of wood |
D．studied the width of the tree rings |
5.Which of he following is true according to the passage?
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A．Young trees have fewer annual rings than old one. |
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B．The trunk of a tree never changes in size. |
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C．Trees in the southwest do not need rain. |
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D．Soil in the southwest is fit for the growth of trees. |
Robison was born in a very poor family. At seven, he had to pick coal in a deserted mine, then he 16 what he had picked and earned a few coins to help his parents. He had 17 schooling. 18 so poor, how could they pay for the education?
When he was fifteen, he worked 19 a servant in a school, looking at other children studying in the classroom, he felt 20 for himself. How he wished to have the same chance. He 21 to study by himself. In the day time after the sweeping and cleaning was over, he 22 stand by the window outside the classroom trying to 23 what the teacher said. At night, he tried his best to remember 24 he had learned during the day. He worked 25 hard at the lessons that he sometimes had just three or four hours’ 26. The more he learned, the 27 he wanted to learn.
A maths teacher 28 him and came to like this diligent(刻苦) boy and 29 him to sit at the back of the class. In 30 exam, he was the one in the whole school who reached the 31 grade.
Robison went on for six years 32 his study of maths and wrote several articles which drew the attention of some university professors. They appreciated (欣赏) his talent and his diligence. 33 him the better chance they employed him as a librarian and 34 him free guidance. Robison was filled with joy. Fro he felt that before him there was a broad road leading to 35.
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It is 10 o’clock now. He _____ be back at any time.
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A．must |
B．should |
C．may |
D．can |
Long years of hard work made _____ possible for him to enter a key university in Beijing.
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A．that |
B．this |
C．it |
D．which |
The small village has _____ a town.
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A．grown up |
B．grown into |
C．brought up |
D．became |
I don’t have the information about SARS, but I’ll _____ later.
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A．find |
B．find it |
C．find out it |
D．find it out |
