题干

下面几种关于导体与绝缘体的说法中正确的是(   )

A:绝缘体没有电子所以不能导电

B:导体内的电荷都会发生移动,所以导体能够导电

C:导体能导电,都是靠自由电子的移动

D:绝缘体不能导电,因为它几乎没有自由电荷

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答案(点此获取答案解析)

D

同类题5

信息归纳:阅读下文,根据所提供的信息,完成下列表格。

Stop Phubbing (别当低头族)

     Last month, Justin Valdez, a college student was shot in subway in San Francisco, the U.S. The surveillance(监控) video showed that before Justin was killed, the killer pulled out the gun several times, and even wiped his nose with it. However, nobody noticed the killer. The surrounding passengers all focused on their mobile phones.

     We may see the same scene everywhere in the life: in subway, restaurants. Elevators, roads, people are watching their mobile phones. From family reunion to date with a friend, people can't stop checking their WeChat, Facebook on the mobile phone and snubbing(无视) the persons in front completely. Not only the young people, but also the olds and the kids.

     “Phubbing” is a new word which comes from the words “phone” and “snub”. It means the habit of snubbing someone in favor of(只顾着) a mobile phone. The word “phubbing” was included in the Australian National Dictionary in 2012. So we can see phubbing is spreading globlly.

     Phubbing seems innocuous(无害的); however, it disturbs our life. Stop posting photos. Let's put down the mobile phone and enjoy the real taste of food and the warmth of interpersonal(人与人之间) communication.

Information Card

The place where Justin Valdez comes from

____

The things that the passengers focused on when Justin Valdez was shot

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The meaning of phubbing

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The time when the word “phubbing” was included in the Australian National Dictionary

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The reason why the writer asks us to stop posting photos

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