题目

“I was in centre school” “_____” A. So were we  B. So we were    C. We were so    D. So did we 答案：20．一些食物近似pH值如下：牛奶6.4，苹果汁3.1，鸡蛋清7.8，葡萄汁4.0，其中酸性最强的是（　　）A．葡萄汁B．鸡蛋清C．牛奶D．苹果汁