氟烷是通过什么机制导致低血压的()
A.心肌抑制使心肌收缩力下降
B.血管扩张致前后负荷降低
C.组胺释放
D.降低交感张力
E.既可使心肌收缩力下降,又扩张外周血管
参考答案:A
— Would you like _____ some milk?
— No, thanks. I don't feel like _____ anything now.[ ]
A. to have, to drink
B. having, to drink
C. having, drinking
D. to have, drinking
许可开始工作的命令,应通知工作负责人,可采用哪些方法?有什么规定?