Knock! Knock! Who’s there? Lettuce…

Knock! Knock! Who’s there? Cargo! Cargo who? Car go beep, beep!

Knock! Knock! Who's there? Opportunity That's impossible. Opportunity doesn't come knocking twice!

Knock! Knock! Who's there? FBI. FB… We're asking the questions here.

Knock! Knock! Who's there? Art Art who? R2-D2, of course.

Knock! Knock! Who's there? Olive. Olive who? Olive you and I don't care who knows it!