—Do you know why the sun looks much bigger on the horizon?

—Well, well,         .I have never read about that.

A．that depends

B．I can’t tell you

C．there is some doubt

D．you really have me there

细菌对氨基糖苷类的耐药机理是：

A．产生灭活酶
B．改变靶位结构
C．二者均有
D．二者均无