风心病二尖瓣狭窄,最易发生的心率失常为()。
A.一度房室传导阻滞
B.心房颤动
C.心室颤动
D.室性期前收缩
E.窦性心动过速
参考答案:B
Your father is sleeping. You’d better ________.
A.wake him up
B.wake up him
C.not to wake him up
D.not wake him up
不同树种的芽,质量是有差异的,这种差异叫芽的异质性。