Carol: I want to join the Bangkok Marathon next month. Tim: ________ (11) ________ Running 42 kilometers is really hard. I’ll never do it. Carol: Of course I’m serious. ________ (12) ________ I started running last week, and I plan to run at least 5 kilometers every day. Yesterday I ran 8 kilometers. Tim: Wow. ________ (13)________ Carol: Thank you. ________ (14) ________ Tim: Play online games. Why? Carol: It will be great if we can exercise together this afternoon. Tim: ________ (15)________ No, thank you. I’m not fit enough.