— When did you go to bed last night?

— Very late. I didn't go to bed _____ my father came back. [ ]

A. until

B. since

C. while

D. after

冠心病心绞痛的心电图表现不正确（）

A.非特异性ST-T改变较常见

B.静息心电图多数出现ST-T改变

C.发作时原倒置T波可以直立

D.冠状动脉造影是诊断冠心病最可靠的方法

E.出现Q波不一定代表心肌梗死