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
The speaker mainly discusses ______.
The speaker mainly discusses ______.
admin
2009-02-10
101
问题
The speaker mainly discusses ______.
In the early 1800s, the paper industry was still using rags as its basic source of fiber as it had for many centuries. However, the rag supply couldn’t keep up with the growing demand for paper. The United States alone was using 250 thou sand tons of rags each year. And a quarter of that had to be imported. It was clear that a new source of fiber was needed to keep up with the demand for paper. The answer to this problem turned out to be paper made from wood pulp, something that was abundantly available in North America. In Canada, the first wood pulp mill was set up in 1866, and it was immediately successful. But while wood pulp solved the problem of quantity, it created a problem of quality. Wood contains a substance called lignin. The simplest way to make large quantities of cheap paper involves leaving the lignin in the wood pulp. But lignin is acidic and its presence in paper has shorted the life expectancy of paper from several centuries for rag paper to less than a century for paper made from wood pulp. This means that books printed less than a hundred years ago are already turning yellow and beginning to disintegrate, even though books printed much earlier may be in fine condition. This is bad enough for the older books on your bookshelf, and it poses a huge problem for libraries and the collections of government documents, too.
选项
A、the growth of the printing industry
B、the history of paper-making
C、the use of paper in the 19th century
D、the composition of wood fiber
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/JR6K777K
0
专业英语四级
相关试题推荐
Culturalpluralismisthedynamicbywhichminoritygroupsparticipatefullyinthedominantsociety,yetmaintainitscultural
Culturalpluralismisthedynamicbywhichminoritygroupsparticipatefullyinthedominantsociety,yetmaintainitscultural
Thereexistsasocialandculturaldisconnectionbetweenjournalistsandtheirreaders,whichhelpsexplainwhythe""standard
Thereexistsasocialandculturaldisconnectionbetweenjournalistsandtheirreaders,whichhelpsexplainwhythe""standard
Inthepast,degreeswereveryunusualinmyfamily.Today,fiveofmybrothersandsistershavedegrees,andtwoarestudying
IseenoconflictinwhattheBibletellsmeaboutGodandwhatsciencetellsmeaboutnature.LikeSt.AugustineinA.D.400,
TheroleofeyecontactinaconversationalexchangebetweentwoAmericansiswelldefined;speakersmakeacontactwiththeey
(1)TheYouTubevideostartswiththeroadsign:Croxteth,CityofLiverpool.Ayouthracesamotorbikedownastreet,anotheren
AlejandroToledo,aformershoe-shineboyturnedeconomist,isnowPeru’sPresident-elect,followinghisvictorySundayinarun
Run,Rabbits,RunFromGreenwichtotheMallisgoodsportforallInits13years,theLondonMarathonhasacquiredap
随机试题
以下不属于手提式水基型灭火器的优点是
患者,男性,65岁,主因咳嗽、咳痰10年,加重伴痰中带血4个月入院。吸烟30余年,20支/d。查体:右肺呼吸音粗,散在细湿啰音。有慢性支气管炎病史10年,无高血压、糖尿病病史。如患者经过纤维支气管检查后,确诊为右上肺腺癌,评估手术适应证,需要进行下列哪
A.TI—AgB.完全抗原C.抗原决定簇D.隐蔽抗原E.共同抗原既有免疫原性又有抗原性的物质是()
在群桩设计中,桩的布置使群桩中心与()的重心尽可能重合,
依据宪法制定机关的不同,可以将宪法分为()。
我国宪法规定,公民有受教育的()。
记得有一位诗人说过这样的话:诗人要做诗,犹如植物要开花,因为他非开不可的缘故。_______你摘去吃了,________中了毒,也是你自己错。
"Inthelongrun,"asJohnMaynardKeynesobserved,"wearealldead."True.Butcanthe【1】runbeelongatedinawaythatmakes
软件测试用例包括()。
YoucanprobablyeatChinese,Italian,andIndianfood______.ThechildrenWhoWanttolearnexcitingdancescangoto______on
最新回复
(
0
)