A terrible earthquake hit Haiti on January l3，2010，_____tens of thousands of people

dead or homeless．

A．1eaving

B．to leave

C．1eft

D．having been left

治疗变异性心绞痛，首选药物为（）

A.β受体阻滞剂

B.钙通道阻滞剂

C.ACEI

D.洋地黄

E.硝酸酯类