国家开放大学 / 综合英语（2）
–I’ve got to go to class this morning. Ed’s sister hasn’t got a key, so if they get here before I get back, would you let them in?
–
–Thanks.
a.Not at all.
b.Yes, please.
c.Sure. No problem.
–
–Thanks.
a.Not at all.
b.Yes, please.
c.Sure. No problem.
参考答案：