题干

有机物A有如图所示的转化关系

已知①有机物B是芳香烃的含氧衍生物,其相对分子质量为108,B中氧的质量分数为14.8%

②CH3CH2COOH+Cl2 →△PCl3   +HCl

③G分子结构中含有3个六元环

根据以上信息,回答下列问题:

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同类题1

阅读理解

     There is plenty of complains about how social media-texting in particular—may be harming children’s social development. But a new study suggests that constant instant messaging(IM’ing) and texting among teens may also provide benefits, particularly for those who are introverted(内向的).

     British researchers studied instant messages exchanged by 231 teens. The researchers analyzed 150 conversations in the study. In 100 of these chats, the study participant began IM’ing while in a negative emotional state such as sadness or anger. The rest were conversations begun when the participant was feeling good or neutral(中立的). After the chat, participants reported about a 20% reduction in their distress—not enough to completely eliminate it, but enough to leave them feeling better than they had before reaching out.

     "Our findings suggest that IM’ing between distressed adolescents and their peers may provide emotional relief and consequently contribute to their well-being," the authors write, noting that previous research has shown that people assigned to talk to a stranger either in real life or online improved their mood in both settings, but even more with IM. And people who talk with their real-life friends online also report feeling closer to them than those who just communicate face-to-face, implying a strengthening of their bond.

     Why would digital communication trump human contact? The reasons may have something to do with the fact that users can control expression of sadness and other emotions via IM without revealing emotional elements like tears that some may consider as embarrassing. Studies also show that the anonymity(匿名) of writing on a device blankets the users in a sense of safety. Previous research has shown that expressive writing itself can "vent" emotions and provide a sense of relief—and doing so, knowing that your words are reaching a sympathetic friend, may provide even more comfort and potentially be helpful. This is what the Internet offers: the change to connect—but in measured doses(剂量) and from behind a screen.

同类题2

清代著名画家郑板桥在《题画》中说:“其实胸中之竹,并不是眼中之竹也。”强调“意在笔先”、“趣在法外”。这说明:(  )

同类题3

半径为2的圆内有两条互相垂直的弦AB和CD,它们的交点E到圆心O的距离等于1,则AB2+CD2=(   )

同类题4

— Would you like        ?  

— No, I've just had some bread.

同类题5

香港和澳门在我国三级行政区划中属于哪一级?(  )
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