I had just finished all my homework and was about to go to bed    the phone rang.

A．when

B．until

C．while

D．before

苯甲酸雌二醇

A．红四氮唑
B．亚硝基铁氰化钠
C．重氮苯磺酸
D．碘化铋钾
E．三氯化锑下列药物鉴别时需要的试剂为