题目

    The easy way out isn't always the easiest.  I learned that lesson when I decided to     treat Doug, my husband of one month, to a special meal.  I    41    to make homemade     bread.  Knowing the bread would take time, I    42    it as soon as Doug left for work.     As l was not    4 3    in cooking, I thought if a dozen was good, two dozen would     be better, so I    44  .everything. As Doug loved oranges, I also opened a can of orange     and    45    it all into the bowl.  Soon there was a sticky dough（面团）covered wit如图所示小球沿水平面通过O点进入半径为R的半圆弧轨道后恰能通过最高点P，然后落回水平面，不计一切阻力，下列说法正确的是（ ）A. 小球落地点离O点的水平距离为RB. 小球落地点时的动能为C. 小球运动到半圆弧最高点P时向心力恰好为零D. 若将半圆弧轨道上部的圆弧截去，其他条件不变，则小球能达到的最大高度比P点高0.5R