首页
登录
职称英语
Plastics are materials which are softened by heat and set into last form 1._
Plastics are materials which are softened by heat and set into last form 1._
游客
2023-12-15
41
管理
问题
Plastics are materials which are softened by heat and set into last form 1.______
when are shaped in a mold. Some are natural; some are semi-synthetic, the 2.______
result of chemical action on natural substance; some are synthetic, built up
from the constituents of oil or coal. All is based on the chemistry of carbon, 3.______
with its capacity of forming chains. The molecules that compose them 4.______
(monomers) link together in the setting or curing process to form chains
(polymers), which give plastics their flexible strength. Some plastics retain
their ability to be softened and reshaped; as wax, they are thermoplastic. 5.______
Others set permanently in the shapes they are given by heat and pressure;
like bags, they are thermosetting.
From industrial beginnings in nineteenth century, plastics have 6.______
struggled through a hundred and twenty years of glory, failure, disrepute
and suspicion on the slow road to public acceptance. Now, at last, one can
positively say that plastics are appreciated and enjoyed for what they are;
that they make modern life rich, more comfortable and convenient, and 7.______
also more fun. Plastics are warm materials, sympathetic with the human 8.______
touch, and their transformation into things that come into contact with human
beings is entirely appropriate.
The fact there are plastic antiques comes as a shock to most people. 9.______
How can a material that seems so essentially twentieth century, and one
that is so much associated with cheap, disposed products, has a history 10.______
at all? It is a young technology, and a great part of the fun of collecting
plastics is that beautiful pieces of historical interest can still be found very
cheaply. [br]
选项
答案
is——are
解析
本题为主谓一致性错误。此句主语为all,谓语动词的单复数取决于all所指代的事物是单数还是复数,此处all指的是上文提到的三种材料,应为复数。
转载请注明原文地址:https://tihaiku.com/zcyy/3274602.html
相关试题推荐
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Whatmaterialswerenotusedforroadsurfacesduringthelastcentury?[br][o
Whatmaterialswerenotusedforroadsurfacesduringthelastcentury?[br][o
Whatmaterialswerenotusedforroadsurfacesduringthelastcentury?[br][o
随机试题
HowwillthemangotoBeijingZoo?[br][originaltext]M:Excuseme.Whichist
Forthispart,youareallowed30minutestowriteashortessayaboutthequali
分项工程质量应在所使用的原材料、半成品、成品及施工控制要点等符合基本要求的规定,
简述我国《教育法》的基本原则。
关于空气过滤器的选择,下列表述正确的是()。A.高效过滤器用于万级以上的洁净
运输爆炸.剧毒和放射性物品,应指派专人押运,押运人员不得少于()人。A.1 B
关于公安消防机构的灭火救援,下列说法正确的是( )。A.公安机关消防机构不负责
期货交易所为债务人的,债权人可以要求人民法院冻结、划拨以下()账户中的资金
根据《民法典》,下列财产不可以抵押的是()。A.生产设备 B.建设用地使
充血A、肝硬化时食管静脉曲张 B、雷诺病 C、槟榔肝 D、急性阑尾炎 E
最新回复
(
0
)