—Why do the people decide ______ these days?

—Because there’s not much to do.

A．visit

B．to visit

C．not visiting

D．not to visit

某种物质的血浆清除率等于肾小球滤过率时意味着（）

A．肾小管对该物质有重吸收作用

B．肾小管对该物质有分泌作用

C．两者均有

D．两者均无