问题
选择题
Sometimes he has some difficulty making decisions on his own,but ______he is independent of others.
A．in all
B．all in all
C．in a word
D．all but
答案
答案：B
all in all意思为 “总的说来”, “总的说来, 他是不受别人约束的人”。 in all总共；总计；in a word总而言之；all but几乎。
示，光滑的水平圆盘中心O处有一个小孔，用细绳穿过小孔，绳两端各系一个小球A和B，两球质量相等，圆盘上的A球做半径为r=20cm的匀速圆周运动，要使B球保持静止状态，求A球的角速度ω应是多大？