options: f : you ruined me ! i will call the police . f : last time you said you would repair this machine . next time you 'd better keep your promise . f : i accepted . but a product of poor quality should be removed from sales list . f : sorry for selling this low-quality product for you , sir .
article: f : i bought this cd in your shop last week , but it suddenly did n't work yesterday and i believed it was not caused by human error . m : sorry . i will change it for you .