答案解析：
What's going on, tracks, express, What the hell were you doing

聽力原文：

Phoebe: Hey, Joey. What's going on?
Joey: Clear the tracks for the boobie payback express. Next stop: Rachel Green. (He goes into the bathroom. We hear a scream and he comes out, closely followed by Monica in a towel)
Monica: Joey!! What the hell were you doing?!
Joey: Sorry. Wrong boobies.
(He leaves. Cut to Monica entering Chandler and Joey's apartment. She sneaks up to the shower door)
Monica: Hello, Joey.
(She whips back the curtain to reveal Joey's dad)
Mr. Tribbiani: Oh! ...Hello, dear. (She whips the curtain shut in horror)