产生感生电动势的非静电力是感生电场对电荷的作用力，产生动生电动势的非静电力是

一热机的循环效率为15%，在一次循环中从外界吸热2000J，则此热机在一次循环中所做的净功为

1mol单原子分子理想气体的温度从0℃升高到100℃，气体的热力学能增加了

劲度系数为k的轻弹簧竖直悬挂，下端连接质量为m的小球，将小球在弹簧原长位置由静止释放，弹簧的最大伸长量为

作用力与反作用力大小相等，方向相反，作用在一条直线上.作用力与反作用力的性质必定

Many other new techniques are now available that enable more research(do) in the test tube to see if chemicals produce harmful biological effects.

He took his umbrella with him lest it(rain).

Every boy and girl(treat) in the same way.

Robots,(become) increasingly prevalent in factories and industrial plants throughout the developed world, are programmed and engineered to perform industrial tasks without human intervention.

One hundred miles(be) too far to travel on foot.