我有很多书怎么说英语

To say "I have many books" in Engpsh, you can say "I have a lot of books" or "I have numerous books." Here are a few more ways you could phrase this in Engpsh:

I have an extensive collection of books.
I have a large number of books.
I have a vast array of books.
I have a plethora of books.
I have a sizable collection of books.

Note that in Engpsh, it is more common to use "a lot of" or "many" to refer to a large quantity of something, rather than "very many" or "very much."