题干

如图,矩形纸片ABCD中,已知AD=8,折叠纸片使AB边与对角线AC重合,点B落在点F处,折痕为AE,且EF=3,则AB的长为(     )

A:3

B:4

C:5

D:6

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答案(点此获取答案解析)

D

同类题3

阅读下文,完成下列各题。

人工智能2.0

    ①“人工智能AI”2017年首次被写入政府工作报告:“加快培育壮大新兴产业,全面实施战略性新兴产业发展规划,加快心态料人工智能、集成电路、生物制药、第五代移动通信等技术研发和转化,做大做强产业集群。”

    ②中国工程院院士、计算机应用专家潘云鹤说,AI当前正处在转折之际,其技术会升级换代。它将通过跨媒体和各种无人技术更紧密的融入人类生活;通过人机会和混合增强智能,成为我们身体的一部分;通过大数据和群体智能,拓展、管理和重组人类的知识,为经济和社会的发展提供建议,在越来越多专门领域的博弈、识别、控制和预测中达到甚至超过人类的能力。“因此,我们将这样的人工智能成为AI2.0。

    ③“30年后的AI2.0必将成为巨人,但是它会在哪些方面展示它与众不同的威力呢?”

    ④在潘云鹤的构想中,到那个时候,大数据智能的研,已经可以为经济智能化运行提供强大的工具,帮助政府和企业从宏观、中观、微观等角度预测经济和市场的走向,前瞻性的创造新产品,进行新投资,确定新政策,从而避免如次贷危机、金融危机等全球性风险,以及产能过剩、库存畸高等问题。市场经济和政府调控相结合的科学基础,使人类经济的运行进入更高水平。

    ⑤对于人类最关心的话题之一——AI2.0对人类健康将产生怎样的影响?潘云鹤料想,“AI用于预防医药,已进入发力阶段”。

    ⑥近年来涌现的各种大型医疗仪器、小型穿戴式设备、大量生理传感器和海量的数字化病力,源源不断地生成人体健康的大数据。将这些大数据汇和分析、学习和提取,就可以预测人体健康的走向和生病的可能。在未来,借助人工智能,高血压、糖尿病、癌症、阿尔茨海默病等疾病,或许能得到预防或者阻断。

    ⑦另一个关于AI的梦想是:人脑和电脑联通。

    ⑧潘云鹤说,人脑和电脑如能直接联合工作,就会形成“脑机混合”增强智能。如果一个学生能轻而易举的记住《新华字典》、唐诗宋词、《古文观止》、四书五经、中国通史、英汉词典、世界地理、中外法律……可以想象,我们的教育,会因此产生怎么样的改变。

    ⑨AI的能力似乎无可估量。可以想象人类未来与AI共存的种种图景:

    ⑩当你在街上碰到陌生人时,系统会产生并处理数据,通过AI程序就能知道你和他的印象如何。

    ⑪在医院里,AI分析X光片的水准,比人类医生还要棒,这些智能机器还可以用于癌症等疾病的到期检查,甚至你上不知晓的情况下采取防治措施。

    ⑫一场彻头彻尾的人工智能革命,真切的出现在我们面前。以色列历史学家尤瓦尔•赫拉利做出预测:未来,大量的工作岗位将被智能机器取代,数十亿人将成为“无用阶层”,社会被少数精英阶层掌控。

    ⑬于是一个关于AI的终极恐惧,进入人类的集体思想——AI会控制人类吗?

(节选自《读者》有删减)

同类题4

请认真阅读下面短文,从短文所给的A、B、C、D四个选项中,选出最佳选项。

    Raynor Winn and her husband Moth became homeless due to their wrong investment. Their savings had been 1 to pay lawyers' fees. To make matters worse, Moth was diagnosed(诊断)with a 2 disease. There was no 3, only pain relief.

    Failing to find any other way out, they decided to make a 4 journey, as they caught sight of an old hikers'(徒步旅行者)guide.

    This was a long journey of unaccustomed hardship and 5 recovery. When leaving home, Raynor and Moth had just £320 in the bank. They planned to keep the 6 low by living on boiled noodles, with the7hamburger shop treat.

    Wild camping is 8 in England. To avoid being caught, the Winns had to get their tent up 9and packed it away early in the morning. The Winns soon discovered that daily hiking in their 50s is a lot 10 than they remember it was in their 20s. Raynor 11 all over and desired a bath. Moth, meanwhile, after an initial 12, found his symptoms were strangely 13 by their daily tiring journey.

    14, the couple found that their bodies turned for the better, with re-found strong muscles that they thought had 15 forever. "Our hair was fried and falling out, nails broken, clothes 16 to a thread, but we were alive."

    During the journey, Raynor began a career as a nature writer. She writes, "17 had taken every material thing from me and left me torn bare, an empty page at the end of a(n) 18 written book. It had also given me a 19, either to leave that page 20 or to keep writing the story with hope. I chose hope."