I know that acc=nom for masculine singular and feminine plural when it is inanimate, and acc=gen when it is animate.
Why: Я не читал этих книг or я не слышу этих слов. when книги is inanimate? Why is it obviously genitive/acc animate? (though слов has to be genitive?)
I thought it should be: Я не читал эти книги (plain accusative inanimate).
and Я не знаю этих людей (accusative animate).