A、She was invited only for the weekend. B、The weather was too hot. C、She had an appointment. D、She had schoolwork to do. D

M: Hey, Karen. Looks like you got some sun this weekend.
W: Yeah, I guess so. I spent the weekend at the beach.
M: Oh, yeah? That’s great! Where did you stay?
W: Some friends of my parents live out there and they invited me for as long as I wanted to stay.
M: So what are you doing back here already?
W: Oh, I have a paper I need to work on, and I just couldn’t do any serious studying at the beach.
M: I don’t blame you. So what did you do out there...I mean besides lie out in the sun, obviously?
W: I jogged up and down the beach and I played some volleyball. You know, I never realized how hard it is to run on sand. I couldn’t even get through a whole game before I had to sit down. It’s much easier to run in the wet sand near the water.
M: Not to mention cooler. Did you go swimming?
W: I wanted to, but they said the water isn’t warm enough for that until a couple of months from now, so I just waded in up to my knee.
M: It all sounds so relaxing. I wish I could get away to the beach like that.
W: It looks like you could use it. Don’t tell me you spent the weekend in the library again.