问题
选择题
—I don't suppose the police know who did it.
—Well, surprisingly they do. A man has been arrested and ______ now.
A．has been questioned
B．is being questioned
C．is questioning
D．has questioned
答案
答案：B
考查被动语态。因a man与question(审问)是被动关系，排除选项C和D；由now可知，要用现在进行时，排除A。
=0.6m。现有一质量为
的小物块A在筒内壁绕中心轴作匀速圆周运动。求当物块在高度为筒高一半的平面内运动时的角速度；
