总效用曲线达到最高点时，( )
A．边际效用达到最大值
B．边际效用为零
C．边际效用为正
D．边际效用为负
参考答案：B
--- is it from your home to the museum? --- About six kilometers.
A．How long
B．How much
C．How far
D．How often
请说说晴雯是如何死的。
