题干
It was last year _____ I visited the museum _____ you had visited.
A：that; that
B：when, where
C：that; where
D：when; that
答案(点此获取答案解析）
A
A：that; that
B：when, where
C：that; where
D：when; that
2HCl ，若用“○”表示氯原子，“●”表示氢原子，则上述反应可表示为（）