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
40
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
B
解析
转载请注明原文地址:https://kaotiyun.com/show/hW9O777K
0
考博英语
相关试题推荐
Yetthedifferenceintoneandlanguagemuststrikeus,sosoonasitisphilosophythatspeaks:thatchangeshouldremindusth
ForthepeoplewhohavenevertraveledacrosstheAtlanticthevoyageisafantasy.Butforthepeoplewhocrossitfrequentlyo
ForthepeoplewhohavenevertraveledacrosstheAtlanticthevoyageisafantasy.Butforthepeoplewhocrossitfrequentlyo
Theoppositeofadaptivedivergenceisaninterestingandfairlycommonexpressionofevolution.Whereasrelatedgroupsoforgan
Battlesarelikemarriages.Theyhaveacertainfundamentalexperiencetheyshareincommon;theydifferinfinitely,butstillt
______totellusthattheinterestoftheindividualshouldbesubordinatetothatofthecollective?
Someweeksago,ridinginacabfromBostontoCambridge,mydriverturnedandaskedmewhatIdidforaliving."TeachEnglish,
Thereisanewtypeofsmalladvertisementbecomingincreasinglycommoninnewspaperclassifiedcolumns.Itissometimesplaced
Thereisanewtypeofsmalladvertisementbecomingincreasinglycommoninnewspaperclassifiedcolumns.Itissometimesplaced
随机试题
患者,男,57岁。腹痛绵绵,时作时上,痛时喜按,大便或溏,神疲畏寒,苔薄白,脉沉细。治疗取穴应首选
不合格药品库(区)的色标颜色为()。
5月10日,甲以自有房屋1套为债权人乙设定抵押并办理抵押登记。6月10日,甲又以该房屋为债权人丙设定抵押,但一直拒绝办理抵押登记。9月10日,甲擅自将该房屋转让给丁并办理了过户登记。下列说法错误的是()。
下列关于出卖人交付标的物的表述中,符合法律规定的是()。
地下管线竣工测量时,当井距大于()m时,除测出井内底管顶或井底高程外,宜加测中间点。
在由江苏省教育厅主办的首届江苏省师范生教学基本功大赛(学前教育专业)上,各项技能比赛竞争激烈,师德问题则是笔试环节的重点。参加竞赛的选手表示,虽然理论笔试没有出现最近广为人知的“温岭虐童”案例,但很多题目都与师德有关系。南京幼儿高等师范学校唐志华校长指出:
下列关于“四个全面”战略布局的说法不正确的是()。
快递员小李需要给一栋大楼的8到17层递送快递,因电梯故障,只能走楼梯,他爬到8楼用时105秒(假设上下楼速度相同),而在每个楼层都有逗留,且逗留的时间恰好为互不相同的不超过10分钟的整数分钟,问从小李进大楼到最后离开需要多少分钟(从门口到楼梯的时间不计)?
Howlongdoesaninterviewusuallylastaccordingtothespeaker?
Lookatthechartbelow.Itshowstheturnoverandprofitofeightcompanies(A-H)inthreeyears.Whichcompanydoeseachsen
最新回复
(
0
)