维拉帕米对哪种心律失常疗效最好（）
A.房室传导阻滞
B.室性心动过速
C.室性期前收缩
D.阵发性室上性心动过速
E.强心苷过量的心律失常
参考答案：D
I have to go now because I must be ____ for class, otherwise, the teacher would scold me. [ ]
A. punctual
B. active
C. sensitive
D. optimistic
19981999＋19991998的尾数是：
A．3
B．6
C．7
D．9
