题干

如图,正方形ABCD和正方形CEFG中,点D在CG上,BC=1,CE=3,H是AF的中点,那么CH的长是(   )

A:2.5

B:5

C:322

D:2

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答案(点此获取答案解析)

B

同类题1

阅读短文,根据题目要求完成各小题。

    In early spring, the changing temperature usually makes a number of Chinese people uncomfortable. Cold air, bringing rain or even snow, easily tears up(破坏) the warmth of the spring within a night(一夜之间).

    However, with the coming of Guyu-the Grain(谷物) Rain, the blue sky and gentle winds would finally stay. Falling usually on or around April 20 every year, Guyu is the sixth of the 24 solar terms(节气). It means the beginning of a lively summer and people get busy from now on.

    Sow(播种) grains

    This is an important period of the growth of grains. The ancient Chinese already knew that as Guyu comes, the weather will become warm enough for sowing. The farmers usually catch the chance to plant rice, corn and beans.

    Hope for safety and harvest

    For those living near the sea, they will hold some ceremonies(仪式) on Guyu, hoping for safety as well as harvest during the coming fishing season.

    Watch the peony

    It's also a great time to see the peony(牡丹), which is known as “the Queen of All Flowers” in Chinese culture. As a result, watching peonies becomes one of the most enjoyable activities for many. The flower is said to be the favourite of Empress(女皇) Wu Zetian of the Tang Dynasty, who was the only woman ruler in Chinese history.

    Pick tea leaves

    Tea leaves picked before Guyu are among the best tea leaves. People believe that the tea leaves picked on the day of Guyu can make eyes clear and drive away bad luck. So the habit of drinking tea at this time of year has become a tradition in some places of China.

同类题3

统一是中国历史的主流。历史学家田余庆教授在论文《中国古代史上的国家统一问题》中对中国历史上的三个统一时期进行了系统的论述。文章的第一部分阐述了国土开发和国家统一的关系。阅读以下相关摘要:
材料一  统一的第一个时期,大体上是西周到秦。西周有一个中央政权,在中国北方黄河流域的范围之内发号施令,让自己的功臣、周室宗亲等等各种各样的人到东方去开辟土地。与周代的制度相比,秦汉所形成的统一否定了周的这个政治制度,但是又不是绝对否定。
材料二 秦汉以后到元是第二个阶段,这个时候中国北方,东部和西部结合在一起,要开发的地区是广大的中国南方。秦统一以后,对开发国土做过一件大事,就是迁徙50万身份低下的或犯了罪的人,到岭南去戍守,把中国南方的国土一直推进到南海边上。这对中国以后逐步开发南方起了很大作用。当然,南方处在落后状态,又有很多民族存在,跟北方交融不那么容易完成。历史为此付出了1000多年的时间。
材料三 到了元以后,中国的统一,从地域方面来说进入了第三个时期,理当是开发大西部。元以后,实际上在东部的南北,没有再出现分裂的可能性,问题在于西部。但是元以后中国缺少开发的条件,广大的西部长期处在一个待开发的落后状态。我们今天开发西部是对于中国统一的进一步巩固开启一个新的起点。美国在1 9世纪开发西部,以至于西部和东部走向平衡,维持了美国今天的国情局面。