The first time I ________ here, it was the year of 1980; this is the third time that I _________ to Chongqing.

A．came; had visited

B．had come; visited

C．came; have visited

D．had come; have visited

患者，男，48岁，因"突发胸痛2小时"就诊。2小时前无明显诱因出现胸痛，疼痛位于心前区，性质为压榨性，向左肩放射，持续约3分钟自行缓解。初步诊断：冠状动脉粥样硬化性心脏病，心绞痛。

目前确诊冠状动脉粥样硬化性心脏病的金标准是（）。

A.心脏X线检查

B.心电图

C.放射性核素检查

D.冠状动脉造影

E.超声心动图