That's why you get all those Cs and Ds, sir.
5 seconds sound clip from the Bon Voyage, Charlie Brown movie soundboard.
You can hear this line at 00:47:07 in the Blu-ray version of the movie.
Quote context
[...]
- What's that you're putting on?
- Pierre says we got to wear tabliers over our clothes.
- This backpack is for our books and school papers.
- We're going to look weird, but I guess if we all look weird, then maybe none of us will look weird.
- I've never carried any books to school in my life.
- That's why you get all those Cs and Ds, sir.
- Hey, Chuck, where's your tablier and backpack?
- My what?
- Are you going to embarrass us on our first day at school?
- I don't know what you're talking about. Nobody's told us anything.
[...]