—Pleasegoonwithyourdemonstration．—ButwherewasI?—Well,yo...

问题详情：

—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

【回答】

B

知识点：过去进行时及其被动式

题型：选择题