A young sales assistant starts work in a hardware shop. The owner says,
"Watch this, I'll show you how it's done."
A customer comes in and ask for a box of grass seed. The owner says,
"Certainly Sir, and I imagine you might be needing a lawnmower for your new lawn?"
After discussion, the customer leaves with a box of grass seed and a lawnmower.
"See," says the owner, "that's how to do it."
A little later another customer enters, approaches the counter and asks for a packet of wallpaper paste.
"Ah" says the sales assistant, "you'll be wanting a lawnmower with that."