()是一种不为应答者提供可选择的答案,让应答者自由地用自己的语言来回答或解释有关想法的问题类型。
A.封闭式问题
B.开放式问题
C.选择式问题
D.填空式问题
参考答案:B
Many years later, the father returned form the army and found that his daughter was no longer ________ she used to be. [ ]
A. what
B. how
C. when
D. whom
如图所示,直径为d的纸制圆筒,使它以角速度ω绕轴O匀速转动,然后使子弹沿直径穿过圆筒。若子弹在圆筒旋转不到半周时在圆筒上留下a、b两个弹孔,已知aO、bO夹角为φ,求子弹的速度。