When I turned to Tony for help, I found that the more he tried to explain, ___________.

A．the more I became confused.

B．the more confused became I

C．the more confused I became

D．I became more confused.

下图为脑组织细胞处血液流动模式图，请据图回答问题：

（1）血管a、c中流的血液分别为________。

A．动脉血、动脉血  B．静脉血、静脉血  C．静脉血、动脉血  D．动脉血、静脉血

（2）组织细胞从b内血液中获得________。

A．氧气、废物  B．二氧化碳、营养  C．氧气、营养  D．二氧化碳、废物

（3）a、b、c内血液流速最慢的是________。

A．a  B．b  C．c  D．难以确定