2--Do you have a sales slip?

1--Here it is.

2--Sorry, things on sale are not allowed to be refunded or exchanged.

1--Oh, but this pair of shoes are a bit too tight. Could I change them for something bigger?

2--All right. Wait a minute.

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注解：
 
1.return退回    
2.sales slip收据  
3.refunded退还   

===================================
译文：

1--我想退了这双鞋。

2--你有收据吗？

1--给你。

2--对不起，减价商品不退不换。

1--哦，但是这双鞋有点小，我能不能换一双大一点的？

2--好的。请稍等。