—Have you finished your homework yet?

—Yes. I _________ it twenty minutes ago.

A．have finished

B．finished

C．will finish

D．had finished

下列哪种疗法不属于高频电疗法（）

A.短波疗法

B.超短波疗法

C.超声波疗法

D.微波疗法

E.毫米波疗法