题干

求下面平行四边形的周长和面积.

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答案(点此获取答案解析)

解:平行四边形的周长:

(8+5)×2,

=13×2,

=26(cm);

平行四边形的面积:8×4=32(cm2);

答:平行四边形的周长是26cm;面积是32cm2

同类题4

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

     The idea of inventing an international language is not a new one. Over the past 180 years, linguists (语言学家) have created over ten different languages that are based on German, Spanish, and English. One of these was Basic English.

     By 1923 the First World War had been over for five years, but Europe was still recovering from its effects. Charles Kay Ogden, a linguist and writer, was running several bookshops in Cambridge. He published The Meaning of Meaning (1923), a book describing how we use language. The book received high praise, which drove Ogden to design an international language — something that was much simpler than English. In 1930 Ogden's book Basic English: A General Introduction with Rules and Grammar was published.

     Perhaps it takes about seven years for one to become a good English speaker. Ogden believed that Basic English could be learned in seven weeks. There were only 850 words and the grammar was very simple.

     The language attracted the attention of educators all over the world, but its development was stopped by the Second World War. After the war, both the British Prime Minister Winston Churchill and the President of the United States Franklin D. Roosevelt looked for ideas that might bring world peace. They both gave speeches that encouraged the use of Ogden's international language. In the past 60 years, the language has had some success. In some parts of East Asia, teachers are still using Ogden's word lists.

     However, in the main, the language has disappeared. Because there are many more non-native than native speakers of English, recently some linguists have asked whether we should give careful consideration to Ogden's ideas again. And the Wikipedia website (www.wikipedia.org) has started a version (版本) written in Basic English for non-native learners of the language. Search for it on the Internet now!  

同类题5

阅读课文《神奇的克隆》,回答问题。

    《西游记》里的孙大圣,紧急关头常常把下一把毫毛,再吹一口气,毫毛立刻变成了一群和自己一模一样的孙悟空。这当然是神话, 不过用今天的科学名词来讲,那就是孙悟空能够快速地克隆自己。  

     我们知道,高等动物一般要通过雄性和雌性生殖细胞的结合,才能繁衍后代,人们把这种繁殖叫做有性繁殖。换句话说,每只动物都有自 己的爸爸妈妈。如果不经过两性细胞结合而直接繁衍后代,就叫无性繁殖,也称克隆。  

     许多植物都有先天克隆的本领。例如,从一棵大树上剪下几根枝条插进土里,枝条就会长成一株株活泼可爱的小柳树;把马铃薯切成许 多小块种进地里,就能收获许多新鲜的马铃薯;把仙人掌切成几块,每块落地不久就会生根,长成新的仙人掌,此外,一些植物还可以通过压 ​条或嫁接培育后代。凡此种种,都是植物的克隆。  

      一些单细胞微生物,如细菌,经过20分钟左右的时间,就可以一分为二,再分为四个、八个,这就是低等生物的克隆。  

      那么,高等生物可不可以克隆呢?从20世纪开始,科学家在这方面进行了卓有成效的研究。1996年,英国科学家成功地克隆出了世界上的 一只克隆羊。这是一项了不起的成就,轰动了当时的科学界。科学家借用一名乡村歌手的名字,给这只克隆羊起名为“多利”。  

      克隆技术是一项可以造福于人类的科技成果。  

      人们将克隆技术与其他科技成果结合,可以根据需要培育出优质、高产的粮食、蔬菜新品种;也可以培育大量品质优良的家畜,大大提高 了饲养效率。  

      克隆技术还可以挽救一些濒危物种,让一些濒临灭绝的动物免遭厄运,从而调节大自然的生态平衡。人们利用克隆技术能够培植人体的皮 ​肤进行植皮手术;能够“制造”出人的耳朵、软骨、肝脏和心脏等人体“配件”,一旦病人需要,就能重新“装配”。  

     神奇的克隆技术正向人类展示它诱人的前景。



“克隆羊”的诞生,为什么在全世界引起“轰动”?