空间分辨力的计算式是（）
A.D=lglo/l
B.K=D1-D2
C.K=ylgKx
D.S=H/K
E.R=1/2d
参考答案：E
—How long _______ in Shanghai?
—I will be there attending a conference and giving a speech, which will take about 3 days.
A．have you stayed
B．are you staying
C．do you stay
D．did you stay
开放式问卷(非结构问卷)中问题的主要形式是( )
A．是否式与选择式
B．评判式与划记式
C．填空式与问答式
D．是否式与评判式
