You made it to class early. You have your pens out, your notebook primed, your eyes on the back of that cute TA’s head. He’s turning around and you’re about to execute a perfect casual hair flip when Sarah sits down in the empty seat beside you, the jostling of her backpack knocking your latte all over your white pants. That’s right — that Sarah, that Sarah from high school, the one who saw you with braces, who was across the cafeteria when your first pimply boyfriend broke up with you. Oh no. This cannot be. You came to college to be someone new, darn it. You even got highlights.

When the Ghost of Yearbooks Past ends up next to you in biology class, you only have so many options. Running into people who’ve seen you break down during puberty, people you only ever knew from group projects and prom, can be like traversing through Dante’s “Inferno” in only your underwear. In short — really sweaty and not at all fun. Use these tips and neither you nor Sarah will break a sweat trying to chit-chat while the professor searches for a working Expo marker.

Smile 

I don’t care if she didn’t give you a tampon that one time you really really needed one, the day you were gonna ask Hot Bryson to the Sadie Hawkins Dance but instead ruined your cute outfit — smile.

Talk politics

You can never go wrong with, “So Trump, right?”

Inquire about their sex life

Ask her if she dumped that guy she dated throughout high school and then into college. Does he still smell like corn dogs and play bass in that “ironic” Nickelback cover band? Is she going to have his babies and if so, will she name one after you?

Throw out a nice compliment

Tell her she looks so different, like you almost didn’t recognize her. Literally you thought she was a model and you were planning to ask if she was in the wrong building. She’s changed so much since high school. She really hasn’t. At all. But everyone likes to hear it.

Market Central

Complain about Market. Connect it to your childhood trauma. Share a bowl of spaghetti and meatballs. When the vibe is right and she’s giving you those eyes, grab the other end of her spaghetti and go for a “Lady and the Tramp” reenactment.

Talk tuition

Complain about the rising price of tuition. Hold a seance to curse Patrick Gallagher — voodoo doll optional.

Help them find true love

During the first half of class, get ordained as a minister online. Then wed her and the TA you were staring at when she sat down. Your professor’s PowerPoint on the makeup of the glucose molecule will look wonderful in the pictures, as will that terrible giraffe-print blouse she’s wearing.

Seal the friendship

Cut out small sections of your hair and braid them into her hair. The two of you are now eternally bonded, sisters of the 9 a.m., friends forever who didn’t know it until this very moment. You’ll see her stand behind you in every mirror you look in for the rest of your life. Not to fear — this is harmless. Drink some orange juice and it’ll go away.

Using one or more of these handy tips, you’ll never have to talk to Sarah about the weather or how much homework you have ever again. You’re now a social god, a master of the faux pas, a regular Chatty Cathy. Whether in class or at a party, on a walk or stumbling through a South Oakland frat house, you’ll know what to do when you see a familiar face.