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
2023-11-23
41
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/3211928.html
相关试题推荐
Usually,therearetworeasonstopursuescientificknowledge:forthesakeof
Usually,therearetworeasonstopursuescientificknowledge:forthesakeof
Usually,therearetworeasonstopursuescientificknowledge:forthesakeof
Usually,therearetworeasonstopursuescientificknowledge:forthesakeof
Usually,therearetworeasonstopursuescientificknowledge:forthesakeof
ThescientificnameistheHoloceneAge,butclimatologistsliketocallour
ThescientificnameistheHoloceneAge,butclimatologistsliketocallour
ThescientificnameistheHoloceneAge,butclimatologistsliketocallour
PassageOne[br]WhatdoesthepartbeforethedashdescribeinPara.7?The
OnFeb.2,2007,theUnitedNationsscientificpanelstudyingclimatechang
随机试题
Whenitcomestomentalhealth,theInternetgetsabadrap.Therearecount
某患者,发现右侧颈动脉三角区肿块3年,渐大,触诊质地软,有弹性及搏动。听诊有血管
未经有效治疗的川崎病患儿冠状动脉瘤的发生率为A.>30% B.10%~15%
M企业在N银行有一笔一年期流动资金贷款即将到期,但M企业集团因季节性因素影响了销
()不是一个具体的险种,而是一种承保方式。A.人寿保险 B.健康保险
老年人阑尾炎()。A.大网膜不易包裹,穿孔率高 B.麦氏点压痛位置高 C.
女,8个月。因进食过量发生腹泻,6~10次/日,体温37.9℃,精神弱,前囟略凹
2020年全国农民工总量28560万人,比上年减少517万人。其中,外出农民工1
在WordXP中,()不能在普通视图中显示出来。A.页眉和页脚 B.分节符
前言(研究背景)
最新回复
(
0
)