红霉素静滴时为防止出现血栓性静脉炎,药物浓度不宜超过
A.3mg/mlB.5mg/mlC.1mg/mlD.0.5mg/mlE.10mg/ml
参考答案:C
Mr. Smith has two sons, one of____working as a bus driver.
A.them
B.who
C.whom
D.whose
一般说来,应收账款拖欠的时间越长,发生坏账的可能性越大。 ( )