Why does the woman say she is concerned?

M: Hi, Jin-Hee, glad to have found you! I’m so sorry I’m late.
W: Oh, don’t worry. I wasn’t waiting that long.
M: I actually arrived early, but I waited in the domestic arrivals area for a while before realizing that international arrivals were in a different terminal.
W: I’ve done that before. Anyway, I have all my bags. Shall we walk down to the train now?
M: OK. So, how was your flight?
W: It was smooth, and I’m happy to be here for the conference. But I’m a little concerned though. I just received an e-mail from my co-presenter. She’s not feeling well and won’t be able to lead the session with me tomorrow.
68.Why was the man late?
69.Look at the graphic. Where will the speakers probably go next?
70.Why does the woman say she is concerned?