题干

如图是研究电流通过导体产生的热量与哪些因素有关的实验,下列分析正确的是(  )

A:甲、乙两次实验都应用了控制变量法

B:甲实验通电一段时间后,左侧容器内空气吸收的热量更多

C:乙实验时为了研究电流产生的热量与电流的关系

D:乙实验通电一段时间后,右侧U形管中液面的高度差比左侧的小

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答案(点此获取答案解析)

A,C,D

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    Rob Frenette had problems with bullies(欺辱) at school for eleven years. He was often lonely and scared. When he was fifteen, however, he decided to do something about his problems. He walked into a newspaper office and told them about the bullying. His story went into the newspaper and soon all the TV stations in Canada wanted to talk to him about his experiences. They also wanted to hear his ideas to stop bullying.

    After that, Rob continued his studies at school, but in his free time he helped other people with bullying problems. With a friend Katie Neu, he made a website called www. bullyingcanada. ca. Visitors to the website can find advice, stories and poems about bullying, in both English and French. When people are upset, they can talk on the phone or online to Rob and his team. Every weekend Rob has to answer e-mails to the website. He also speaks to children, teachers and members of government around the country about bullying.

    Rob's most important message is: “When bullies are unkind to you, it isn't your fault (过错、责任). There's nothing wrong with you, so you should try to keep trusting yourself. And remember that people care about your problems. You just have to find those people.”

    One of Rob's ideas is “Blue Day”, a special day for stopping bullying in schools. Students have to wear blue clothes and in class they learn how to stop bullying. More than 150 Canadian schools now celebrate Blue Day, but Rob won't stop until there's a Blue Day in every school in Canada.