甲状腺功能亢进症的特征性心血管症状是()。

A．心律失常

B．睡眠时心率仍快

C．毛细血管搏动征

D．奇脉

E．水冲脉

We were on the point of discussing financial investment_____ the telephone rang unexpectedly.

A．while

B．when

C．as

D．once