Why do you want a new job_____ you've got such a good one already?   [ ]

A. that          

B. while        

C. which        

D. when

强心苷类药禁用于( )

A．慢性心功能不全
B．心房纤颤
C．室性心动过速
D．心房扑动
E．房性心动过速