室颤患者首选治疗措施是（）。 A.观察瞳孔是否散大固定 B.触摸大动脉搏动 C.人工

离合器的主、从动部分常处于分离状态。

— How can I help you?

—    小题1:    

— Would you like to send it surface or airmail?

—   小题2:   

— If you send the parcel with surface email, it will take about 2 months to arrive, whereas with airmail, it will arrive in one week or more.

— That’s a big difference. 小题3:　 How much will it cost to send it airmail?

— That depends on the weight. Place it on the scale, please.

— OK.

— That’s 300 grams.     小题4:  

— That’s not bad. I’ll do that then. Does that include insurance on the contents of the parcel or is that a separate payment?

—     小题5:  It’s another 5 pounds.

— OK.

A．I suppose airmail will be much more expensive.

B．I want to buy some stamps.

C．I’d like to send this package to China.

D．That’s separate.E. That’s all right.

F. What’s the difference between surface and airmail?

G. It will cost 10 pounds for airmail.

如果不能保证四个小时的睡眠，那么大脑将不能得到好的休息；如果大脑得不到很好的休息，第二天大部分人都会感觉到精神疲劳。
因此，可以推断（）。

A．只要大脑得到充分休息，就能充分消除精神疲劳

B．大部分人的精神疲劳来源于睡眠不足

C．如果你只睡三小时，你们第二天一定会精神疲劳

D．如果大脑得到了很好的休息，则必然保证了四个小时的睡眠

毒物进入体内的总量超过转化和排出总量时，体内的毒物就会逐渐增加，这种现象称为毒物的积蓄。毒物在体内的积蓄是发生（）的基础。

A.急性中毒

B.慢性中毒

C.亚急性中毒

求曲面积分I=

dzdx+2dxdy，其中S是球面x²+y²+z²=4外侧在z≥0的部分．