题干

在探究“电压一定时,电流与电阻关系”的实验中,电路如图所示。先在A、B间接入5Ω的定值电阻R,移动滑片P,使电压表示数为2V,读出电流表示数。取下5Ω的电阻换上10Ω定值电阻,不进行其它操作就闭合开关。此时电压表示数及应进行的操作是(   )

A:电压表示数大于2V,应将滑片P向左滑

B:电压表示数大于2V,应将滑片P向右滑

C:电压表示数小于2V,应将滑片P向左滑

D:电压表示数小于2V,应将滑片P向右滑

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答案(点此获取答案解析)

B

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阅读理解

    Many of us still tend to think that emotions can affect reasonable thought,and sometimes land us in trouble. But in recent years psychologists have taken quite a different view. Keith Oatley,Professor of Psychology at Glasgow University,is involved in the research which shows the fundamental importance of emotions.

    He believes we are very ambivalent about them:we think of our emotions as being unreasonable,but we also consider them as essential to being human. For example,Mr. Spock,a character in the television series Star Trek,is super­intelligent and he has no emotions at all. However,he is never made captain of the spaceship. Maybe,this is because Mr Spock is not the kind of person you can share your feelings with—a person who shows his emotions.

    As Professor Oatley points out,our emotions have very important functions,for example,fear. If we cross the road and a car approaches,we usually stop moving or step back. We stop what we are doing,check what we have done and pay very careful attention to the environment. The emotion of fear makes us take this small series of actions which,on average, help protect our safety.

    On the other hand,if things are going well and small problems come up,we find we can solve them with the resources we have to hand. As a consequence, we tend to feel happy and usually continue doing the job.

    Anger is an emotion that tends to occur when someone is preventing us from doing something. Then this small “kit” of reactions enables us to prepare ourselves to be quite aggressive to that person,or to try harder,and so on.

    Professor Oatley believes emotions generally occur at these important moments in actions. With fear and anger our emotions make us decide to start doing something else, while with happiness they “suggest” we continue what we are already doing.