首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Trees are so common arid quiet that we pay them little mind. What, for instance, should we answer when asked to name the biggest
Trees are so common arid quiet that we pay them little mind. What, for instance, should we answer when asked to name the biggest
admin
2012-10-23
48
问题
Trees are so common arid quiet that we pay them little mind. What, for instance, should we answer when asked to name the biggest living thing Earth has ever seen? Dinosaurs? Blue whales? No, the largest sequoias in northern California weigh more than six blue whales. The tallest redwoods and Australian eucalyptus trees tower more than 300 feet high, three times the length of the greatest dinosaur.【71】Some bristlecone pine trees in the American West are more than 4, 000 years old, seedlings at the time the Egyptians were building the Pyramids. Trees sustain our lives and our planet in a thousand practical ways. This morning at breakfast—in your wood-framed house, on your wooden kitchen table—you might have enjoyed orange juice or a grapefruit. Both come to use from trees. Over your French toast you may have sprinkled cinnamon and nutmeg, the powdered bark and nuts of tropical trees. That quart of maple syrup on your table was boiled down from roughly 10 gallons of sap from a sugar-maple tree.【72】Do you like chocolate, almonds, cola beverages.’? Cocoa beans, almonds and kola nuts are tree products. Frees do more than mule life pleasant; they make life possible. Trees get water through their roots and, primarily through their leaves, they draw carbon dioxide from the air. Then, with the action of sunlight on cells containing chlorophyll and other materials, chemical reactions occur, and oxygen is released.【73】Photosynthesis also produces glucose, a type of sugar. Trees convert some of the glucose to starch, which they use for energy storage. The cellulose fiber we call wood is made of thousands of glucose molecules linked into giant chains that no longer taste sweet.【74】The ancient Greeks, for example, treated pain with a tea made by boiling willow leaves and bark, a tea modern scientists now know contains silicon, a precursor of acetylsalicylic acid—aspirin.【75】More recently, researchers isolated and synthesized the chemical ginkgolide from the tree for use in treating asthma, toxic shock and other ills.
A. For centuries, the Chinese have derived medicines from the ginkgo tree.
B. Through photosynthesis, an acre of trees produces enough oxygen to sustain three humans.
C. As scientists unlock the secrets of trees, they uncover surprising tacts.
D. Trees have always been green machines, producing substances that humans learned to use.
E. You think, at 150 or more years, giant tortoises can live a long time?
F. And the morning newspaper was printed on the processed wood pulp we call paper.
选项
答案
E
解析
转载请注明原文地址:https://kaotiyun.com/show/LW9O777K
0
考博英语
相关试题推荐
Aneducationshouldenableastudenttogetabetterjobthanhewould______beabletofindorfill.
ForthepeoplewhohavenevertraveledacrosstheAtlanticthevoyageisafantasy.Butforthepeoplewhocrossitfrequentlyo
ForthepeoplewhohavenevertraveledacrosstheAtlanticthevoyageisafantasy.Butforthepeoplewhocrossitfrequentlyo
ForthepeoplewhohavenevertraveledacrosstheAtlanticthevoyageisafantasy.Butforthepeoplewhocrossitfrequentlyo
ForthepeoplewhohavenevertraveledacrosstheAtlanticthevoyageisafantasy.Butforthepeoplewhocrossitfrequentlyo
ForthepeoplewhohavenevertraveledacrosstheAtlanticthevoyageisafantasy.Butforthepeoplewhocrossitfrequentlyo
Theoppositeofadaptivedivergenceisaninterestingandfairlycommonexpressionofevolution.Whereasrelatedgroupsoforgan
Battlesarelikemarriages.Theyhaveacertainfundamentalexperiencetheyshareincommon;theydifferinfinitely,butstillt
Hewasconcernedonlywithmundanematters,especiallythedailystockmarketquotations.
Someweeksago,ridinginacabfromBostontoCambridge,mydriverturnedandaskedmewhatIdidforaliving."TeachEnglish,
随机试题
当填充金属一定时,熔深的大小取决于焊缝的化学成分。
储存式自身输血的一次采血剂量不超过
干粉输送管道进行气密性试验时,对干粉输送管道,试验压力为水压强度试验压力的()。
全断面法属于隧道分类中的()
为判断会计账户记录是否正确,常采用编制试算平衡表的方法。只要该试算平衡表实现试算平衡,即说明账户记录正确无误。()
根据《刑事诉讼法》,律师作为犯罪嫌疑人、被告人的辩护人,在刑事诉讼中享有的诉讼权利包括()等。
企业在确定最佳估计数时,不应当综合考虑与或有事项有天的货币时间价值因素。()
经鉴定不能出境的文物,国家可以()
【B1】【B16】
Totheeditor,Thanksforgoodqualitynewsyourcompanyprovidetoourcommunity.AnarticlepublishedintheMay20issueofW
最新回复
(
0
)