(one) is not as green as (one) is cabbage-looking

One is smarter or less naïve than one seems. A: "Hey, that dopey intern did a great job on this report." B: "Wow. I guess he's not as green as he is cabbage-looking." Good job not falling for that trick. You're not as green as you are cabbage-looking. Today is April Fool's Day—time for you freshmen to prove that you're not as green as you are cabbage-looking.