戴眼镜的那位姑娘着一身红色.
with 用法很广,不用强调“戴”这个动作时,用这个介词就行了.如果你写成 the girl who has a pair of glasses is in red.一大堆定语从句便很累赘,很臃肿.
类似用法有：
The park with a lake is right beside my home.
The old lady with a basket is walking along the street.