题干

把一个平行四边形拉成一个长方形,它的周长是____,面积是____

A.变大    B.不变    C.变小    D.无法比较

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答案(点此获取答案解析)

B,A

同类题1

阅读下面文字,回答小题。

阳光,是一种语言

雷抒雁

    ①早晨.阳光以一种最明亮、最透彻的语言和树叶攀谈,绿色的叶子,立即兴奋地颤抖,通体透亮,像是一页页黄金锻打的箔片,炫耀在枝头。而当阳光微笑着与草地上的鲜花对语,花朵便立即昂起头来,那些蜷缩在一起的忧郁的花辫,也迅即展开,像一个个恭听教诲的耳朵。

    ②晴朗的日子,走在街上,你不会留意阳光。普照的阳光,有时像是在对大众演讲的平庸演说家,让人昏昏欲睡,到处是燥热的嘈杂。

    ③阳光动听的声音,响在暗夜之后的日出,严寒之后的春天,以及黑夜到来前的黄昏。这些时刻,阳光会以动情的语言向你诉说重逢的喜悦、友情的温暖和哪怕是因十分短暂的离别而产生的愁绪。

    ④倘若是雨后的斜阳,彩虹将尽情展示阳光语言的才华与荚丽。赤、橙、黄、绿、青、蓝、紫,从远处的山根,腾空而起,瞬间飞起一道虹桥,使你的整个身心从地面立刻飞上天空。现实的郁闷,会被一种浪漫的想象所消解。阳光的语言,此刻充满智慧,让你理解天雨花,石点头;让你平凡生活的狭窄,变成一片无边无垠的开阔;让你枯寂日子的单调,变得丰富多彩。

    ⑤可这一切,只是一种语言,你不可以将那金黄的叶子当成黄金;江河之上,那些在粼波里晃动的金箔也非真实;你更不要去攀援那七彩的虹桥,那是阳光的话语展示给你的不可琢磨的意境。瞬间,一切都会不复存在。可是,这一切又都不是空虚的,它们在你的心中留下切切实实的图画,在你的血管里推涌起波澜壮阔的浪潮,在你耳边轰响着长留不息的呼喊,使你不能不相信阳光的力量和它真实的存在。

    ⑥和阳光对话,感受光明、温暖、向上、力量。即使不用铜号和鼙鼓,即使是喃喃私语,那声音里也没有卑琐和阴暗,没有湿淋淋的、怯懦者的哀伤。

    ⑦你得像一个辛勤的淘金者,从闪动在白杨翻转的叶子上的光点里,把握阳光的语言节奏;你得像一个朴实的农夫,把手指插进松软的泥土里,感知阳光温暖的语言力度。如果你是阳光的朋友,就会有一副红润健康的面孔和一窗明亮清朗的心境。

    ⑧阳光,是一种语言,一种可以听懂的语言。

同类题3

阅读理解

    Life may have evolved on at least three planets within a newly discovered solar system 39 light years from Earth. Astronomers at the NASA have discovered no less than seven roughly Earth-sized worlds orbiting a dwarf star in the system. Scientists had previously identified a tiny number of "exoplanets", which are believed to have the qualities needed to support life. However, the new system contains an unprecedented(前所未有) number of Earth-sized, probably rocky planets, and is being acknowledged as an "accelerated leap forward" in the search for extraterrestrial (外星球的)life.

    Three of the new planets are said to be particularly promising because there might exist oceans. Thomas Zurbuchen, associate administrator of NASA, told a press conference in Washington: "This gives us a hint that finding a second Earth is not a matter of 'if', but 'when'."

    The planets were discovered using NASA's Spitzer Space Telescope, which was able to track how fast each of the planets crossed the star Trappist-l and completed an orbit. From this the research team calculated how far the planets were from their star, and therefore how likely they are to be habitable.

    NASA's Hubble Space Telescope is already being used to search for atmospheres around the planets. Future telescopes, including the proposed European Extremely Large Telescope and the James Webb Space Telescope, may be powerful enough to discover markers of life, such as oxygen in the atmospheres of exoplanets.

    Astronomers believe there could be as many as 40 billion potentially habitable worlds in our galaxy, the Milky Way. Prof Zurbuchen said that now was a "gold-rush phase" in the search for these exoplanets.

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