治疗急性心肌梗死引起的室性心动过速首选药物是

A．尼莫地平
B．硝苯地平
C．维拉帕米
D．利多卡因
E．奎尼丁

Experiments of this kind   in both the U．S．and Europe well before the Second World War．

A．have conducted

B．have been conducted

C．had conducted

D．had been conducted