17.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(分層) of new wood each year it lives.If you look at a tree stump (樹根),you can see the layers.They are called annual rings (年輪).
On some trees,all of the rings are of the same width.But the ponderosa (美國黃松) that grow in the Arican southwest have rings in different width.The soil in the 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 form an annual record of past rainfall in the southwest.
66.We could infer from the passage thatA.
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 the same width every year
D.the ponderosa grows in the southeast
67.A tree grows a new layer of woodC.
A.each week B.whenever it rains C.every year D.every season
68.On the whole,this passage is aboutB.
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
69.The scientistsDto know how much rain fell in a certain area in the past.
A.climbed up the trees
B.moved the pine tree
C.removed a piece of wood
D.studied the width of the tree rings
70.Which of the following does the passage lead you to believe﹖A
A.Young trees have fewer annual rings than old ones.
B.The trunk of a tree never changed in size.
C.Trees in the southwest do not need rain.
D.The soil in the southwest is fit for the growth of trees.
分析 本文講述了科學(xué)家用研究樹的年輪的方法來了解過去的降雨.
解答 66.A推理題:根據(jù)文章內(nèi)容科學(xué)家研究樹的年輪來判斷降雨量,再結(jié)合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.在雨量充足的年份,樹長的好,干燥季節(jié),長勢不好,結(jié)合選項可以推斷出答案是A
67.C細節(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
68.B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
69.D細節(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.
70.A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.一些松樹幾百歲,有許多年輪可以推理出A正確.
點評 本文是人文地理類閱讀理解.這類題材是高考?純(nèi)容,它注重考查考生對整體內(nèi)容的把握,做題時要求考生結(jié)合題目及文章上下文做出正確的選擇.