中心静脉压的正常值为
A.30~50mmH2OB.50~80mmH2OC.50~120mmH2OD.80~120mmH2OE.80~150mmH2O
参考答案:C
— Is John coming by train?
— He should, but he _____ not. He likes driving his car. [ ]
A. must
B. can
C. may
D. need
下列参数与等标污染负荷计算有关的是
A.慢性毒作用阈剂量B.成人平均体重C.成人每日呼吸量D.环境质量分指数E.污染物排放标准