Knock, Knock!

helen:Isn't there anyone at home?
jim:I'll knock again, Helen. Everything's very quiet. I'm sure there's no one at home.
helen:But that's impossible. Carol and Tom invited us to lunch. Look through the window.
helen:Can you see anything?
jim:Nothing at all.
helen:Let's try the back door.
jim:Look! Everyone's in the garden.
carol:Hello, Helen. Hello, Jim.
tom:Everybody wants to have lunch in the garden. It's nice and warm out here.
carol:Come and have something to drink.
jim:Thanks, Carol. May I have a glass of beer please?
carol:Beer? There's none left. You can have some lemonade.
jim:Lemonade!
tom:Don't believe her, Jim. She's only joking. Have some beer!