【场景再现】

Rachel去和Barry说分手，结果是两个人在牙医的椅子上sex，Ross知道以后觉得很难接受

All: Hey! Hi!
Phoebe: How'd he take it?
Rachel: Pretty well, actually... (Wandering into the kitchen.)
Monica: (wandering in after her) Uh, Rach... how come you have dental floss in your hair?
Rachel: Oh, do I?
Monica: Uh huh.
Rachel: (in a low voice) We ended up having sex in his chair.
Monica: You had sex in his chair?!... I said that a little too loudly, didn't I?
Ross: You-you had what?
Phoebe: Sex in his chair.
Ross: What, uh... what were you thinking?
Rachel: I don't know! I mean, we still care about each other. There's a history there. 'S'like you and Carol.
Ross: No! No no, it is nothing like me and Carol!
Rachel: Please. If she said to you, "Ross, I want you on this couch, right here, right now," what would you say? (Ross flounders.)
Chandler: If it helps, I could slide over.
Ross: It's, it's, it's, uh, a totally diferent situation! It's, it's apples and oranges, it's, it's orthodontists and lesbi- I gotta go.
Phoebe: Where are you going?
Ross: (leaving) I just have to go, all right? Do I need a reason? Huh? I mean I have things to do with my life, I have a jam packed schedule, and I am late- for keeping up with it. Okay?

【讲解】

keep up with 跟上

You're walking too fast. I can't keep up with you.
你走得太快了，我跟不上。

At first he couldn't keep up with the class.
开始时，他跟不上班。