题干

____还保留着猿的一些体质特征,但已经能够____,上肢基本上具备了现代人的特点。随着四肢的分化和手的发展,脑也在缓慢地进化。这些变化说明____    在从猿到人的进化过程中起了重要作用。

上一题 下一题 0.0难度 选择题 更新时间:2017-06-09 12:01:24

答案(点此获取答案解析)

北京人,制造和使用工具,劳动

同类题2

完形填空

    In the middle of a beautiful day, I was feeling lost, as if the world was crashing on me. didn't know which way to go, except to head out to the countryside. I went to the spot where I used to take my kids-when I still had kids. Now they had  1and were leaving.

I was sitting alone in my car when I saw a man in his seventies, whose problem appeared bigger than mine. He stood near the edge of the road,2a kite spindle(风筝线锭) in his hands. Apparently, lost in thought, he stared skyward. I 3my neck to see how successful he had been in 4 the clouds. Following his string with my eyes, I almost lost5 of the other end. Finally, the kite rested on what seemed to be the highest branch of the 6tree in the park.  Obviously,  that was his grandson's kite!  The kite was a replica (复制品) of a beautiful bald eagle, and its wings spread 70pen. Grandpa had only one 8to his problem: cut the string.

"You wanted it to fly as high as it could. Bill. didn't you?" "Yes, Grandpa,9 wanted to keep it forever. " "There just comes a time when the only thing you can do is to cut the string and let it go. Perhaps by doing that, when it flies very high like real eagles do, it will come back to us. " Grandpa said.

    I 10 how the old man cut the string to let fly the kite. As the two walked away, looked to the 11. There I saw my answer, too. Today I have to cut the final strings that kept my two boys 12my reach. Though I want to keep them forever, I have taught them to fly like an eagle. Maybe by doing this, when it's time to soar like real eagles do. one day they would come back to me.

同类题5

阅读下文,回答问题

未来,木星会取代太阳吗?

    ①在太阳系中,木星是行星中的“巨无霸”。它的体积和质量分别达到了地球的1320倍和318倍。不过,除此以外,木星的独特之处还在于它能发光,有自己的能源。

    ②也许你并不觉得这是什么稀罕事,那么我们先来看一下行星的定义:行星通常是指自身不发光、环绕着恒星的天体。其公转方向常与所绕恒星的自转方向相同。一般来说行星需具有一定质量,行星的质量要足够的大且近似于圆球状,自身不能像恒星那样发生核聚变反应。在人们的通常认识中,行星的确不能发光,只能依靠反射太阳的光线。但科学家研究发现,木星正在把巨大的能量不断地向周围的宇宙空间释放,它释放的能量,相当于两倍从太阳那里所获得的能量,说明木星有一半的能量来自它的内部。

    ③分别于1972年和1973年发射的“先驱者”10号与11号飞船探测的结果显示,液态氢构成了整个木星。它同太阳一样,没有坚硬的外壳,主要是通过对流形式来实现能量的释放。前苏联科学家齐巴罗夫和苏齐科夫认为,木星的核心温度已达到30000℃之高,热核反应还在其内部继续进行。

    ④那么,我们不禁要问一个严肃的问题:未来,木星会渐渐取代太阳吗?

    ⑤正如之前所说,木星是由液态氢构成的,本身并无坚硬的外壳。木星的这种构成与太阳构成方式十分相似,主要是通过对流形式来实现能量的释放。木星不仅把自己的引力能转换成热能,还在不断吸收太阳释放的能量,这就使它的能量越来越大,且热度越来越高,并使它达到了现在的高度。从木星目前的发展趋势看,它很可能成为太阳系中与太阳相差无几的第二颗恒星。

    ⑥30亿年以后,太阳到了晚年,木星很可能取代太阳的地位。虽然时间还很远,但人类不得不面对一个事实是,太阳已经是一颗垂暮的恒星了,它的光辉总有一天会熄灭,而木星的自带光源,点燃了生命顽强延续下去的希望。

(选自《探索与发现》2016年第5期,略有改动)