高中英语问题 请告诉我原因 38.14

题目

高中英语问题 请告诉我原因 38.14
____that he was going to the supermarket,so i asked him to send a letter for me
a.that happened
b.it so happed
c.that was happened
d.it was happened

答案

选B
it so happened that为固定结构,意为恰巧,其中so还可以省略.