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
7
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
FiveTipsforStudyingAmericanRevolutionAmericanRevolution—
材料题 B Inthefallof1924ThomasWolfe
检测尿中β-微球蛋白是监测A.恶性肿瘤 B.泌尿系感染 C.肾小管功能 D
根据《合同法》规定,导游员李某与甲旅行社的劳动合同终止后,关于李某和甲旅行社间的
2017年我国进口额和出口额最多的国家或地区分别为:A.欧盟和东盟 B
善祛经络风痰的是A.白芥子B.天南星C.紫菀D.昆布E.半夏
分离培养霍乱弧菌( )。A.碱性琼脂平板 B.吕氏血清斜面 C.疱肉培养基
关于法律职业道德的理解,下列哪一说法不能成立?A、法律职业道德与其他职业道德相比
国债发行额占中央财政支出的比重用()来表示A.国债发行规模 B.国债依存度
某泵是叶片式泵的一种,泵体是水平中开式,进口管呈喇叭型,适用于扬程低流量大的送水
最新回复
(
0
)