—I have been working hard at math.  However, I can't get good marks in the exam.              

—Go on studying hard. And I think your dream will ________ .             [ ]

A. come true              

B. come back              

C. come out                

D. come up with

下列MLS系统的类型中，（）运作形式的交易过程比较规范，但卖方需支付较多的佣金费用。

A.强制性的MLS系统

B.自愿性的MLS系统

C.独家代理的MLS系统

D.仅买方代理的MLS系统