HHI指数的优势在于().
A.必须收集到该市场上所有企业的市场份额信
B.计算量不大
C.HHI对规模最大的前几个企业的市场份额变化反映特别敏感
D.便于收集资料
参考答案:C
Don’t forget to the lights before you leave the classroom.
A. turn on B. turn off C. turn up
----Will you watch the World Cup match this year?
------No. I _________ several World Cup matches since I was a small child.
a. had seen b. see
c. was seeing d. have seen