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
32
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] 【C12】
选项
A、concentrated
B、concentrating
C、concentration
D、concentrate
答案
A
解析
此题考查非谓语动词的用法。这里我们要看主语the light from a laser和动词concentrate之间的关系是被动还是主动:主动用-ing形式,而被动则用-ed形式。该句中为被动,所以正确答案为A项concentrated。
转载请注明原文地址:https://tihaiku.com/zcyy/3826496.html
相关试题推荐
"let’stakeawalkbeforewestarttostudy.""Oh,Ithinkit’s_______forwalki
Thescientificgroupiscarryingoutaresearchfocusedonadrugwhichisso__
Ascientificdiscoveryisoftenmade【C1】______beforesomeoneisabletopu
Ascientificdiscoveryisoftenmade【C1】______beforesomeoneisabletopu
Ascientificdiscoveryisoftenmade【C1】______beforesomeoneisabletopu
Ascientificdiscoveryisoftenmade【C1】______beforesomeoneisabletopu
Ascientificdiscoveryisoftenmade【C1】______beforesomeoneisabletopu
Ascientificdiscoveryisoftenmade【C1】______beforesomeoneisabletopu
Ascientificdiscoveryisoftenmade【C1】______beforesomeoneisabletopu
Ascientificdiscoveryisoftenmade【C1】______beforesomeoneisabletopu
随机试题
Ifpetownershaveaneyewithfashion,theycandresstheirpetsinstylishclo
CarsaccountforhalftheoilconsumedinTheU.S.,abouthalftheurban
Forthelastfiftyyears,theglobehasbeenwarmingup.Itistruethat
Itisplaincommonsense--themorehappinessyoufeel,thelessunhappiness
[originaltext]W:Oh,I’mfedupwithmyjob.M:Hey,thereisaperfectjobfor
观察交换机状态指示灯可以初步判断交换机故障,交换机运行中指示灯显示红色表示()
监督机构在基础和结构阶段应()安排监督检查。A、每季度 B、每月 C、每周
具有泻下通便、清肝、杀虫作用的是A.芦荟 B.苦楝皮 C.番泻叶 D
关于21-三体综合征下列哪项不正确A.本病不属于常染色体畸变 B.小儿染色体病
(2016年真题)采用滑模摊铺机施工法铺筑连续配筋混凝土路面时,布料最适合采用(
最新回复
(
0
)