what does yur new English teacher look like?--------she is a pretty lady__long hair

为什么是with...

为什么是with

with在这里的用法有having, possessing, or carrying something的意思
examples:
a tall gentleman with a grey beard
a book with a green cover
a man with a gun
We need someone with bright new ideas.
Only people with plenty of money can afford to shop here.
She came back with a letter in her hand.

只有脸部或身体上的用with,而穿着类的当然用in喽

with long hair 介词短语做定语，她是一位留着长发的漂亮女孩。