What do Richard Branson, Jack Dorsey, and Michelle Obama all have in common? Besides being ____(extreme) successful, each of them is known for____(wake) up very early. The three famous persons' examples tell us how this habit can make a____(different) in life,____can help you ,too.

    Early rising is helpful in more than one way. To begin with, it helps us to have good health. The air is never____fresh as early in the morning. Early rising gives you time to take exercise. Besides, early rising helps us in our studies. In the morning we learn more quickly and find____Easy to learn something by heart. At last, early rising makes people able____(plan) the work for the day. We can't work well____a good plan. Just as a year's plan starts with spring, the plan for the day ought to____(make) in the morning. Therefore, if you want to____(success),it's a good idea to jump out of bed earlier.

设集合A={x|x²﹣3x+2=0}，则满足A∪B={0，1，2}的集合B的个数是（　　）

如图所示，光滑绝缘体杆竖直放置，它与以正点电荷Q为圆心的某一圆交于B、C两点，质量为m，带电荷量为﹣q的有孔小球从杆上的A点无初速度下滑，已知q远小于Q，AB=h，小球滑到B点时速度大小为 $\sqrt{3gh}$ ，则小球从A运动到B的过程中，电场力做多少功？若取A点电势为零，C点的电势是多大？