选择填空。

— May I speak to Jim, please?

— Sorry, ______ now. [ ]

A. I'm not Jim

B. this is me

C. he isn't at home

和静脉血相比，动脉血（　　）

A．颜色鲜红，含二氧化碳较多

B．颜色暗红，含二氧化碳较多

C．颜色鲜红，含氧较多

D．颜色暗红，含氧较多