I have been facing a difficulty understanding the usage between singular or plural forms in situations like this:
I give them a book.
I give them books.
If my understanding is right, the first sentence means I give a group of people just ONE book, while the second means I give a group of people more than one book. However, the following sentence sounds just alright to me, and I have seen some similar uses thrown around on the Internet.
The activity helps them develop a keener sense of body awareness.
My question is, if this is grammatically correct, why does it use "a sense of" while the activity should have helped each of them develop a keener sense, which sums up to more than one sense? Or should it be:
The activity helps them develop keener senses of body awareness.