A: I can't read my book.
B: Turn on the light.
A: The light is on.
B: Open the book.
A: The book is open.
B: See an eye doctor.
A: That's what I need to do.
B: He'll give you a prescription for glasses.
A: I'll make an appointment tomorrow.
B: I'll get the yellow pages for an eye doctor.
A: Read the phone number to me.
B: I'll read it very loud, in case your hearing is getting bad, too.