— Is Mr Smith rich?  

— Yes, very rich. When he worked in ________town, he earned a lot. Now he has a big farm in ________ country.  

A．at; the

B．/; /　　　　　　

C．/; the

D．the; /

下列指标中（）不是CD-ROM的主要性能指标.

A.容量

B.体积

C.存取时间

D.转速