the schools in their area not of high enough quality to meet their needs 这里的of

题目

the schools in their area not of high enough quality to meet their needs 这里的of

答案

原句少了一个are吧（not前）,这里是一个结构问题, be of +抽象名词=be +形容词,of high enough quality其实就是qualified的意思,表示“高质量的”,(这个地方的学校质量不够高,难以满足他们的需求）再如
He is of great help= He is very helpful
The English learning is of great importance=The English learning is very important