—How do you study____ a test?

--I study____working_______my classmates.

A．for , in , with

B．for, by, at

C．for, by, with

D．of, in, by

善于治疗膏淋的药物是（）

A.滑石

B.萆薢

C.石韦

D.车前子

E.海金沙