Hi Claudia! "I pay a book" is not correct English. It's more common to say: "I paid for a book" if it's in the past, or "I am paying for a book right now" if it's in the present. You can also use "buy" as the verb: "I am buying a pair of glasses", or "I bought some shorts yesterday". Does that help? Ryan

I pay for a book. I pay for a bike. I pay for glasses. I pay for shorts. subject + pay(s) + for + something How much do you pay for a book? I pay 3 dollars for each book at that store. I pay Carla $30 for her help every week. I pay the waitress for the food when I am finished. I pay Tom for my share of the pizza when he brings it here. I pay the water company $5 every month. subject + pay(s) + someone + for + something With a price: subject + pay(s) + price + for + something

They are not so natural. “For” should be added.