A、He has stayed on campus. B、He has been in an academic conference. C、He has been ill in hospital. D、He has been on vocation. DW

W: Rex, can you give me a hand with one of those bags?
M: Sure, Lucy.
W: Could you take this one please? I didn’t realize how heavy these bags would be.
M: Why did you borrow so many books from the library when you have to walk back to your room from there?
W: Well, I didn’t intend to. Indeed, most of the books aren’t mine. On my way back I met two classmates who asked me to bring their stuff as they were going to a party. And I’m also going there later, you know, after 1 drop all these bags.
M: What’s the occasion?
W: Our professor, Prof Lee, has been on vacation for a month and we thought we’d surprise him. We’re getting together for a welcome party.
M: Oh, that’s really thoughtful of you.
W: We figure it’s the least we can do for him. He’s really helped me a lot with my last term paper.
M: Really? That’s very kind of him.
W: Well, he understood how difficult it was to submit the paper by the deadline when I was in the hospital, so he granted me a month’s extension. He’s been such a big help to me. I thought that this might be a small way to thank him.