属于内暴露水平测定是
A．脏器系数B．血铅C．饮水中氟化物含量D．血中胆碱酯酶活性E．脂/水分配系数
参考答案：B
乙型肝炎的潜伏期是
A．1周 B．2～6周 C．7～12周 D．6周至6个月 E．半年以上
It’s annoying ! After I gave her my advice, my daughter ________ go and do the opposite.
A．have to
B．must
C．shall
D．would
