题干
—Did your father enjoy seeing his old friends yesterday?
—Yes, he did. They each other for ages.
A：didn't see
B：wouldn't see
C：haven't seen
D：hadn't seen
答案(点此获取答案解析）
D
min后，测得各物质的浓度分别为c(X2)＝0.4 mol·L－1，c(Y2)＝0.6 mol·L－1，c(Z)＝0.4 mol·L－1，则该反应的化学方程式可表示为