题目

－What did you say just now?     －I asked if _______ TV last night.     A. did you watchB. you watched C. are you watchingD. you are watching 答案：B4．某工厂生产甲乙丙三种不同型号的产品，三种产品产量之比为1：3：5，现用分层抽样的方法抽得容量为n的样本进行质量检测，已知抽得乙种型号的产品12件，则n=36．