7个同学一组，来春游的人正好分成6组，每组一位老师带队，你知道参加春游的师生一共有几人吗？
6×7+6= 48（人）
Do you know what ______ the little boy? [ ]
A. happened has to
B. happened with
C. has happened to
D. have happened
什么叫催化剂的热崩？
