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
25
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
are (shaped)一/
解析
本题为赘词错误。此处为when引导的状语从句,主语为materials,因与主句主语一致而被省略,这种情况下,谓语动词是be动词的应当一起省略,如:When hurt women tend to confide in their friends。
转载请注明原文地址:https://tihaiku.com/zcyy/3274601.html
相关试题推荐
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Plasticsarematerialswhicharesoftenedbyheatandsetintolastform1._
Whatmaterialswerenotusedforroadsurfacesduringthelastcentury?[br][o
Whatmaterialswerenotusedforroadsurfacesduringthelastcentury?[br][o
Whatmaterialswerenotusedforroadsurfacesduringthelastcentury?[origina
随机试题
[originaltext]W:It’sawfullydarkfor5o’clock.Doyouthinkit’sgoingtora
Peoplewholivedintownsandcitiescouldeasilyrefreshthemselvesinthe
[originaltext]W:Ihaveaveryimportantappointmenttoattendthisafternoon.
事务T1中有两次查询学生表中的男生人数,在这两次查询执行中间,事务T2对学生表中
A.口腔行使各种功能运动时,基牙及支持组织不发生下沉、松动、移位等 B.基牙牙
最易引起气血凝滞的邪气是A.风 B.寒 C.湿 D.燥 E.火
吸气时每分钟进入肺泡进行交换的气量,称为()。A.潮气量 B.肺泡通气量
商品指数基金在交易上的共性有()。A.各类商品指数中均包含能源、贵金属、基
用于建设项目偿债能力分析的指标是()。A.总投资收益率 B.利息备付
2017年1月10日,甲公司以银行存款5110万元(含交易费用10万元)购入乙
最新回复
(
0
)