Every one holds a book in his hand. Should I say "their book" or "their books"?

Question

Every one holds a book in his hand. Should I say "their book" or "their books"?

Answer 1

Their books. "Books" needs to be pluralized because you are speaking of multiple books.

If you are going to speak to everyone like individuals however, then it is correct to say, "Everyone take your book and..." The "your" makes it alright to leave "book" singular because in this example you are speaking of each book individually. Otherwise, "Everyone take their books" is what you're looking for.

Their: more than one person: plural noun, books.

Your: one person. Singular noun, book.

Answer 2

pluralized-book turns into 2 books.

you would say :"Can you pass my BOOKS"

Answer 3

Their book = many authors, one book.

Their books = many books, many owners.

Answer 4

Just substitute book with a different word, like foot.

Everyone holds a foot in his hand. Their feet...

It wouldn't make sense not pluralising it in this instance so it makes sense you'd pluralise it.