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问题 填空题

力的三要素分别是力的大小、方向和______．用手拍桌面，手会感到疼，这是因为______．

答案

（1）力的三要素是指力的大小、方向、作用点；

（2）用手拍桌子，手对桌子施加力的同时，桌子也给手一个力的作用，因为物体间力的作用是相互的，从而手感到疼．

故答案为：作用点；相互的．

单项选择题

下列说法正确的是（）.

A．气体的温度升高时，分子的热运动变得剧烈，分子的平均动能增大，撞击器壁时对器壁的作用力增大，从而气体的压强一定增大

B．气体的体积变小时，单位体积的分子数增多，单位时间内打到器壁单位面积上的分子数增多，从而气体的压强一定增大

C．压缩一定量的气体，气体的内能一定增加

D．分子a从远处趋近固定不动的分子b，当a到达受b的作用力为零处时，a的动能一定最大
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单项选择题

The British show a great love for the countryside and it is really nice and beautiful. A lot of people dream (梦想) about living in the countryside, to enjoy the quiet and the air. Today, many people, both old and young, make the dream come true. But most people have to live in a town or city because that is where the work is.
People of a city are often proud (自豪的) of living in it. People of Manchester believes that there is no better city than Manchester; people of Liverpool feel the same way about Liverpool. Outsiders and passing travelers may be interested in what the difference is between one city and another. Maybe they remember Newcastle because of its bridge over the River Tyne, or Liverpool because of its docks (码头). There is one difference which most people can hear; that is the different ways of speaking and also some words which are used only in one place. In Newcastle, for example, "hoy" is used instead of "throw", and "marra" instead of "friend", as is shown in the sentence "Hoy the ball to me", and "He’s my marra at work in the factory.\

A city is usually remembered for ______.
[A] what there is in the center of it
[B] the number of people living in it
[C] what makes it different from other cities
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