燃油滤清器吏换前为何要进行燃油系统泄压操作？

A. Sure. What time?
B. Why not? When should I be there?
C. Why?

A. No.
B. I'd love to, but I have an appointment.
C. I'm busy tonight. Can I take a raincheck?

A. Thank you very much! I'd be delighted to.
B. I'd love to, but I'm afraid I'm busy this Saturday.
C. I don't go out on Saturdays.

A. Yes, I would.
B. Thank you. I'd love to.
C. I'm sorry but I already have plans tonight.