Question

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 (樹干) keeps growing year by year. Under its bark (樹皮), 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 (年輪).

On some trees, all of the rings are of the same width. But the ponderosa(美國黃松) 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 ______.

A．a(chǎn) tree grows faster when it has a lot of water

B．scientists cut down trees to study tree rings

C．pine trees form rings of he same width every year

D．the ponderosa grows in he southeast

2.A tree grows a new layer of wood _____.

A．each week

B．whenever it rains

C．every year

D．every season

3.On the whole, the passage is about _____.

A．why the tree trunks grow bigger

B．why scientists study tree rings

C．trees that lived hundreds of years ago

D．the ponderosa in the US

4.The scientists _____ to know how much rain fell in a certain area in the past.

A．climbed up the tree	B．moved the pine tree
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?

A．Young trees have fewer annual rings than old one.

B．The trunk of a tree never changes in size.

C．Trees in the southwest do not need rain.

D．Soil in the southwest is fit for the growth of trees.

 

Answer 1

【答案】

1.A

2.C

3.B

4.D

5.A

【解析】

1.推理題：從第一段的內(nèi)容可以推斷出答案是A

2.細(xì)節(jié)題:從文章第二段的句子：A tree’s trunk (樹干) keeps growing year by year.說明每年樹都會長一層新的。選C

3.主旨題：從第一段的句子：Because scientists need a way to learn about past rainfall, they study the tree rings.說明文章講的是科學(xué)家為什么要研究年輪。選B

4.細(xì)節(jié)題：從文章倒數(shù)第二段的句子：Then they look at the width of each ring to see how much rain fell in the year it formed.說明科學(xué)家是研究年輪的寬度來知道某個時間的降雨量。選D。

5.推理題：從文章最后一段的句子：Some pines are hundreds of years old and have hundreds of rings. 可以推理出A正確。