i was ___when you called me.i had my hair cut

问题描述:

i was ___when you called me.i had my hair cut
A in the hairdresser's
B at a hairdresser
C at the hairdresser's
D in a hairdresser
为什么?顺道问问 at on in有什么区别

“在某人(的某地)处”固定用at,
at (the) 某人's
就是这样了,固定搭配