题干

光斜射到平面镜上,入射光线与镜面的夹角为30°,反射角为(  )

A:0°

B:30°

C:60°

D:90°

上一题 下一题 0.0难度 选择题 更新时间:2015-06-05 05:27:08

答案(点此获取答案解析)

C

同类题2

Li Ting,15,from Shanghai, was preparing a talk on some western festivals. She searched online for certain information and made PowerPoint presentations(展示).

Wu Qiong,her classmate, was doing his chemistry homework carefully. But he couldn’t work out the last problem even he tried his best. So he took out his mobile phone, opened a special app(应用软件),and searched the problem. Answers soon appeared on the screen in several seconds.

Nowadays, many students do homework online with the help of the Internet like Li and Wu. They search information online, use apps or discuss through QQ and We chat.

“It's convenient. You don't have to wait for your teacher to explain it to you face to face. "According to Wu." You can also learn by seeing how others work them out. What's more, it improves students' abilities. And it's especially true for new kinds of homework. I am quite skilled at finding information online and using Microsoft Office.”

However, this trend(趋势) also causes problems. Some lazy students just copy the answers online without thinking. Even some ask their classmates to do homework for them. And their teachers don't know the fact.

Anyhow, knowing how to use the Internet is important. The key is to have good self-control. When you come across(遇到) a difficult problem, think about it by yourself first. Be sure to understand the reasons behind the answers after you have turned to the Internet, or you won’t make progress. If you are not sure about your self-control, ask your parents for help.

同类题5

阅读材料,完成下列要求。

材料一  2016年7月4日,***在全国国有企业改革座谈会上强调,国有企业是壮大国家综合实力、保障人民共同利益的重要力量,必须理直气壮做强做优做大,不断增强活力、影响力、抗风险能力,实现国有资产保值增值。阅读下列关于S市企业改革的相关材料并回答。

材料二  2016年6月29日,上海国际信息消费节以主题展览形式召开,形成线上线下、场内场外、全城互动,向大众展示上海在“互联网+”时代的信息经济建设成果。信息消费一端连着各阶层消费人群,一端连着广大终端制造业和电商、物流等多个行业。信息消费所承载的新型商务、支付等模式将极大降低社会交易成本,推动传统产业的商业模式创新和向价值链高端的迁移。有数据表明:信息消费每增加100亿元,将带动国民经济增长338亿元。

    2016年,我国信息消费规模超过3.9万亿元,名副其实成为国家新的支柱产业之一。未来5—10年,中国将成为世界最大的电子商务市场,网络创业将促进就业规模不断扩大、就业质量不断提高。

以微信为例,2016年,微信拉动全社会消费4475亿元,同比增长37.6%。其中,微信带动信息消费1743亿元,带动传统消费2732亿元;微信带动社会就业规模达1881万人,同比增长7.7%。其中直接就业466万人,间接就业1415万人。