题干

在式子
x
2
(
x>0)
,2,y+1(y=−2),−2x(x<0),33,x2+1,x+y 中,二次根式有(   )

A:2个

B:3个

C:4个

D:5个

上一题 下一题 0.0难度 选择题 更新时间:2019-11-04 05:01:55

答案(点此获取答案解析)

C

同类题1

阅读材料,完成下列各题。

材料一:1685年,康熙皇帝宣布取消海禁,实行“开海贸易”,并设立粵、闽、浙、江四大海关管理对外贸易和征收关税,此后,来华从事贸易的外国商人日益增多,但当时的清政府并没有成型的外贸体制,无力接待外来商船。于是,粤海关官府招募了十三家较有实力的商行,代理海外贸易业务,并代官府管理外商和执行外事任务,俗称“十三行”。……专设经理广州外贸税饷事务的洋行制度,乃是清廷实施严格管理外贸政策措施的重要内容和组成部分,其目的是“杜民夷之争论,立中外之大防”。1757年,乾隆下令“一口通商”,四大海关仅留广东一处,广州十三行成为清帝国唯一合法的外贸特区,中国与世界的贸易全部聚集于此……18世纪80年代英国东印度公司取得英国对华贸易垄断权后,十三行的贸易对象主要是英国。1842年“十三行”在战火中走向消亡。

材料二:英国东印度公司创立于1600年,最初的正式全名是“伦敦商人在东印度贸易的公司”。它是由一群有创业心和有影响力的商人所组成。这些商人在1600年12月31日获得了英国皇家给予他们的对东印度的15年的贸易专利特许。……1609年,詹姆士一世向东印度公司发出了一张不设期限的特许状,特许状只会在公司连续三年没有盈利的情况下才会被取消。1670年,查理二世发布了五条法律,授予东印度公司自主占领地盘、铸造钱币、指挥要塞和军队、结盟和宣战、签订和平条约和在被占据区就民事和刑事诉讼进行审判的权力。东印度公司的敌人包括商业竞争者、敌对国家和国内的敌对势力,因此它需要更多的保护权利。1680年,公司建立了一支自己的武装力量。1858年,英国取消东印度公司。

——以上材料均摘编自百度百科

同类题5

阅读理解

    Science has a lot of uses. It can uncover laws of nature, cure diseases, make bombs, and help bridges to stand up. Indeed science is so good at what it does that there's always a temptation(诱惑) to drag it into problems where it may not be helpful. David Brooks, author of The Social Animal: The Hidden Sources of Love, Character,and Achievement, appears to be the latest in a long line of writers who have failed to resist the temptation.

    Brooks gained fame for several books. His latest book The Social Animal, however, is more ambitious and serious than his earlier books. It is an attempt to deal with a set of weighty topics. The book focuses on big questions: What has science revealed about human nature? What are the sources of character? And why are some people happy and successful while others aren't?

    To answer these questions, Brooks surveys a wide range of disciplines(学科). Considering this, you might expect the book to be a dry recitation of facts. But Brooks has structured his book in an unorthodox(非常规的), and perhaps unfortunate, way. Instead of introducing scientific theories, he tells a story, within which he tries to make his points, perhaps in order to keep the reader's attention.So as Harold and Erica, the hero and heroine in his story, live through childhood, we hear about the science of child development and as they begin to date we hear about the theory of sexual attraction. Brooks carries this through to the death of one of his characters.

    On the whole, Brooks' story is acceptable if uninspired. As one would expect, his writing is mostly clear and, to be fair, some chapters stand out above the rest. I enjoyed, for instance, the chapter in which Harold discovers how to think on his own. While Harold and Erica are certainly not strong or memorable characters, the more serious problems with The Social Animal lie elsewhere. These problems partly involve Brooks' attempt to translate his tale into science.