—I called you at six o'clock yesterday evening but there was no reply.

—Oh, I'm sorry. I _______ dinner at my friend's. [ ]

A. was having

B. is having

C. had

D. have

临产的先兆症状是（）

A.胎膜破裂

B.宫缩25s，间歇8～20min

C.宫颈消失

D. * * 排出少量血性黏液

E.子宫底下降