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
2014-03-21
23
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、turned out high-quality paper
B、used wood imported from the United States
C、caused a serious environmental problem
D、was a ready market for its product
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/EtUK777K
0
专业英语四级
相关试题推荐
Manypeoplebelievethatsciencehelpssocietytoprogressthrough______.WhichofthefollowingstatementsisINCORRECTabout
Decidewhichofthechoicesgivenbelowwouldbestcompletethepassageifinsertedinthecorrespondingblanks.Markthebestc
Heknowswheretheyarebound,andhow.Bycrossingthroughthejungleonfoot,youmay______themattheirnextstop.
PeopleinLatinAmericawearsomething______toexpresstheirhopesforwealthintheNewYear.
IntheUnitedStatesthefirstdaynurserywasopenedin1854.Nurserieswereestablishedinvariousareasduringthe【C1】______
"OntheInternet,nobodyknowsyou’readog,"readthetitleofafamousPeterSteinercartoon,(1)_____nowhereisittruertha
InSeptember,morethanadozenwhalesbeachedthemselvesintheCanaryIslands.Rescuerstriedtowaterdownthewhalesandkee
Threeofthefourmeninthecaraccidentwereslightlyinjured,and______
It’shightimewe______cuttingdowntherainforests.
随机试题
根据行政诉讼法的规定,人民法院对具体行政行为的变更仅限于显失公正的行政处罚。()
A.温胆汤B.茯苓丸C.滚痰丸D.小陷胸汤E.清气化痰丸(2000年第91,92题)胸脘痞闷,喘咳痰稠,大便秘结,或惊悸癫狂,舌苔黄厚,脉滑者,治宜选用()
日规定剂量(DDD)只是
建设单位将建设工程肢解发包的,责令改正,处工程()的罚款;对全部或者部分使用国有资金的项目,并可以暂停项目执行或者暂停资金拨付。
在本职工作之外从事的、不计报酬的服务性或公益性工作,可称为()。
【2015年吉林吉林】提升教师职业道德修养的方法包括()。
轨道环绕太阳的天体有()。
管理者往往对直观信息熟视无睹,对数字情有独钟。结果,他们就可能_________一些关键线索,不能真正了解到对方的优势和劣势。由此导致的结果,要么是“_________”,要么是“交友不慎”。
设关系模式R<U,F>,其中U={H,I,J,K,L},若F={H→IJ,J→K,IJK→L,L→H,L→K),则F的最小函数依赖集Fmin={(1)_____},关系模式R的候选关键字有(2)_____个,R属于(3)_____。(3)
下列叙述中正确的是( )。
最新回复
(
0
)