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
33
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/ItUK777K
0
专业英语四级
相关试题推荐
Theythenbeganthelongandtiresome______ofpreparingthemselvesforcollegeentranceexamination.
What’sthepercentageoftheunhealthychildrenbythetimetheygraduatedfromhighschool?
______somanyprofitshavebeenmadeinthepastthreeyearsisthestrongestargumentforcontinuingthebusiness.
Languageisnot______throughoutthecountrybutfallsintodialects.
Anewstudyofthebrainishelpingscientistsbetterunderstandhowhumansprocesslanguage.Oneofthepatientsisawomanwit
WhathadChineseAmericansbeenassociatedformanyyearsintheUnitedStates?
TonyWilliamswasworkingasacar-park______inLosAngeles.
MrSmithhadanunusual______;hewasfirstanofficeclerk,thenasailor,andendedupasaschoolteacher.
AlthoughtherearemanyskillfulBraillereaders,thousandsofotherblindpeoplefinditdifficulttolearnthatsystem.Theya
Toerrishumanandtoforgivedivine,accordingtotheoldadage.Humanswhoforgiveare(1)______toexperiencesignificantphys
随机试题
求曲线处的切华斜率.
对于急性心肌梗死并发心脏破裂,下列哪项不正确()(1995年)
A尿卟啉B尿本周蛋白C尿胆红素D尿胆原E尿肌红蛋白Ehrlieh试验用于检测
远距离摄影是指焦-片距
纳洛酮临床用于治疗()。
下列哪种情形构成诬告陷害罪?(卷二真题试卷第13题)
中国公民张先生为国内某企业高级技术员工,2014年度取得的收入如下:(1)每月工资12000元,12月份取得双薪工资12000元,同时取得全年一次奖金56000元。(2)5月受邀为某大学讲课一个月,大学代缴其个人所得税,取得大学支付的报
胆汁主要是对()进行消化和吸收。
以下关于集体合同的说法,不正确的是()
根据下列材料回答下列问题。2009年1—4月我国完成城镇固定资产投资为37082.30亿元,比去年同期增长30.5%,其中第一产业比去年同期增长82.1%,投资比重见下图。2009年14月我国完成城镇固定资产投资中第三产业多少亿元?(
最新回复
(
0
)