---I am afraid that I have to trouble you with this question.

---___________.

A．No,you cannot

B．Go ahead

C．Not at all

D．I don’t mind

是指在一个相当长的时期内，总体经济活动朝着某一个方向呈现出有规律的变动趋势。______

A．长期趋势
B．商业循环
C．季节波动
D．偶然波动