A、Sam. B、Ted. C、Ruby. D、Sam’s girlfriend. A本题问的是谁支付午餐费用。本题的关键是理解That will be my treat，该习语意为“我请客”。虽然Ruby提出了“AA制”，但是Sam强烈表示他支付午餐的费

M: Hi, Ruby, have you heard that there is going to be a robot show at the museum?
W: Yes. And they say students can get half-price tickets. Sam, are you planning to go?
M: Yes.(15)And I have invited my girlfriend to go with me.(14)So I wonder if I could borrow your car this Sunday.
W: Well, would you please wait just a moment and let me check my schedule?
M: OK.
W: Well,(12)today is Friday and Ted wants to meet with me on Sunday, so that we can talk about next week’s experiment. But I guess I can call him and put it off to the next Monday. The experiment is on Wednesday. Um, Sam,(15)do you mind me joining you to go to the robot show? Or you want it to be a trip with your girlfriend only?
M: Are you kidding? Of course I don’t mind. By the way, we can have lunch together at the Mexico restaurant just next to the museum. I heard they have really nice food and the price isn’t high.(13)That will be my treat.
W: I think it’s better if we go Dutch.
M:(13)I do want to pay for it. I appreciate your driving us to the museum. In this weather, we would shake all over if we have to wait for the bus.
W: All right, then.(14)(15)I’ll pick you up at 8:00 Sunday morning. Then, we can pick up your girlfriend at about 8:20.
M: Thank you. See you on Sunday.
W: See you.
12. What did Ruby plan to do on Sunday?
13. Who will pay for the lunch?
14. When will they go to the robot show?
15. How many people will go to the robot show?