-Hello, Sandy. This is Jack. What are you doing?

-I’m watching a match. It started at 7 p.m. and _____ on for another half an hour.

A．has been

B．was

C．had been

D．will be

有关重症肌无力的临床表现，下列哪项不对（）

A.休息后缓解

B.新斯的明试验阴性

C.肌电图示低频重复递减

D.晨轻暮重

E.可伴胸腺瘤