— What's wrong, Mary? You look sad.

— Oh, nothing much. In fact, I _____ of my English test.  [ ]

A. think

B. was thinking

C. will thing

D. would think

通过（），可以降低保险人的交易成本。

A.保险代理人

B.保险经纪人

C.保险精算师

D.保险律师