What is the difference between the following expressions: I read and I have read?

Question

I read a book
I have read a book 
and I had read a book 
What is the difference between each of the following sentences ?

Answer

1. This is a present tense noun, eg "I am currently doing this"
2. This is a noun being said in the present about the past, eg "I did do this"
3. I dont know how to describe this but its like "I have done this"

What is the difference between the following expressions: I read and I have read?

Answers (1)