—I wonder why Suzan looks worried today.

—I’m not sure, but she ________a small accident driving here.

A．could have

B．might have

C．might have had

D．must have had

不属于循环系统疾病的重要实验室检查项目的是（）

A.放射性核素检查

B.超声心动图

C.心导管术和心血管造影

D.糖耐量试验