Question

Mary heard somebody call her,so she turned ( ) to

Mary heard somebody call her,so she turned ( ) to see who it was.
为什么是around，不是out?

Answer 1

turn around 是转身的意思，turn out有两个常用的意思：（1）“结果是，结局是”,后面常接to be 或者that 语句。
It turned out that he was lying。结果是他在说谎。
(2)出现，出场
比如： A vast crowd turned out to watch the match.大群的观众到场观看比赛

Answer 2

turn around转身