首页
登录
职称英语
A scientific discovery is often made【C1】______ before someone is able to pu
A scientific discovery is often made【C1】______ before someone is able to pu
游客
2024-11-01
1
管理
问题
A scientific discovery is often made【C1】______ before someone is able to put it to use.【C2】______ , scientists discovered how to split atoms decades【C3】______ the invention of the atomic bomb and the use of【C4】______ power to produce electricity. But sometimes discovery and【C5】______ happen at the same time, as occurred more than thirty years ago【C6】______ the discovery of coherent light and the invention of the laser.
The word laser【C7】______ "light amplification by stimulated emission of radiation. To many people, lasers are very mysterious, but a laser is simply a【C8】______ that produces a strong light. The light from the laser is called【C9】______ light because it is light that only moves in one direction.【C10】______ , incoherent light, like the light from the sun or light from a bulb, moves away from its source【C11】______ all directions, so its strength is very spread out. The light from a laser, moving in only one direction and【C12】______ in a narrow beam, is much stronger. Laser light is created by a【C13】______ called stimulated emission. In this process, the atoms of a certain substance, such as a crystal or a gas, are excited 【C14】______ that they produce coherent light. A person working with a laser can aim this coherent light,【C15】______ a laser beam, in any direction.
As soon as the laser was developed, scientists began thinking of practical applications【C16】______ it. One of the earliest uses was to make extremely precise measurements of distance and speed.【C17】______ , the distance to the moon was measured to within a foot, and the speed of light was measured to 【C18】______ a thousandth of a mile per second. As time【C19】______ , many more applications for the laser were【C20】______ . [br] 【C3】
选项
A、by
B、before
C、after
D、since
答案
B
解析
此题考查表示时间的介词的用法。既然第一句中用了long before,这里谈到原子裂变,将这个时间具体化,所以要说decades before,意思是原子裂变发现几十年之后才出现了该成果的应用。所以,惟有 B项符合题意。这个题也说明了做这类完形填空题中上下文相互参照的重要性。
转载请注明原文地址:https://tihaiku.com/zcyy/3826487.html
相关试题推荐
Signhasbecomeascientifichotbutton.Onlyinthepast20yearshavespe
Signhasbecomeascientifichotbutton.Onlyinthepast20yearshavespe
Signhasbecomeascientifichotbutton.Onlyinthepast20yearshavespe
Didyouhearsomeone______inthenextroomalllastnight?A、movingaboutB、movi
Ifthewholeopera,on______beforehand,agreatdealoftimeandmoneywouldh
Mysister’sprofessorhadher______herpapermanytimesbeforeallowingherto
DecadesbeforetheAmericanRevolutionof1776,JesseFish,anativeNewYo
DecadesbeforetheAmericanRevolutionof1776,JesseFish,anativeNewYo
Fornearlyacenturybeforetherewassuchathingasaspaceprogram,aview
Fornearlyacenturybeforetherewassuchathingasaspaceprogram,aview
随机试题
[originaltext][3]FriendsReunited—oneoftheUK’sfirstsocialnetworks—has
"TheEvolutionofBirds"BirdsBeganasFeatheredRepti
Manypeopletodayareworriedaboutbirdflu.Theyareafraidthatitwillp
以下所示水准测量数据的记录,正确的是().A.1.3m B.1.30m C
多层民用建筑(除住宅外)高度()m的均为高层建筑。A、20 B、22 C、2
2,3,4,9,10,这五个数的几何平均数是()。A:3.81 B:4.20
为了提升学员线上学习的获得感,某公司专门设置了督学岗位督促学员学习。某日有甲、乙
必须在工程设计文件上签字的人员中应有()。A.注册执业人员 B.注册建筑师和
A.三十五味沉香丸 B.十一味金色丸 C.大月晶丸 D.十三味冥丸 E.
球阀是近年来发展最快的阀门品种之一,其特点有( )。A.适用于溶剂.酸等介质
最新回复
(
0
)