问题
选择题
—Please go on with your demonstration．
—But where was I?
—Well, you_____the two chemicals together．
A．tried to mix
B．were trying to mix
C．were trying mixed
D．had tried to mix
答案
答案：B
根据句意是：--请继续你的演示。---到哪儿啦？---你想把两种化学物质混合起来。说明是刚才正在做…,用过去进行时。选B。