扩张静脉和动脉，起效快，维持时间短的是
A．硝酸甘油B．肼屈嗪C．哌唑嗪D．硝苯地平E．硝普钠
参考答案：E
Thomas is the very person I think is worth making friends with．
A．whom
B．who
C．which
D．whoever
机车一般采用直流它激电动机做牵引。
