从一副混合后的扑克牌(52张)中，随机抽取1张．事件A为“抽得红桃K”，事件B为“抽得黑桃”，则概率P(A∪B)=（ ）(结果用最简分数表示)．
— Have you got the news about Jack? I haven't seen him for many years.
— He _____ in a company for two years. Now he is a teacher. [ ]
A. worked
B. has worked
C. had worked
D. would work
中药饮片
A．限于一名患者的用药B．应当在修改处签名并注明修改日期C．单独开具处方D．分别开具处方，也可以开具一张处方E．每一种药品应当另起一行，每张处方不得超过5种药品
