how to understand the phrase"be of+ noun"?
I know that be of noun is equal the adjective of noun, just like this book is of little value, is equal this book is valueless, so does it mean be of equal has, I mean it seems this book has little value also can express the same meaning.

Question

how  to  understand the  phrase"be  of+ noun"?
I  know that  be of noun is  equal the  adjective of noun, just  like this  book  is  of  little value, is equal this book is  valueless, so does it mean be  of equal has,  I  mean  it  seems this  book  has little  value also can  express the  same meaning.

Answer

I'm not sure I understand your question but I'll try to answer anyway.  You're suggesting that "be of" = "has" and you're asking if this generally true?

No, I don't think so.  Consider "This is a book of great importance" = "This book has great importance".  That doesn't sound quite right to my native ears but maybe it's okay.  So then lets consider "This book is of a type that we have not yet seen" = "This book has a type that we have not yet seen".  These meanings are not the same.