she was a bit nervous as she __her boy friend's parents.

问题描述:

she was a bit nervous as she __her boy friend's parents.
A has never seen B didn't see
C had never seen D not having seen
为什么选C

she was a bit nervous as she had never seen her boy friend's parents.
为什么不选C.,
她有点紧张,因为她从未见过她男友的父母.
这里的as的意思是 因为