刚来美国读书的时候，觉得这里可以在超市用ATM卡付帐顺便取点现金这一条真方便。有一次就有了下面的对话。

Cashier: Did you find everything all right?
Me: Sure.
Cashier: Credit or Debit?
Me: Debit. By the way, I want some trash back.
Cashier: #$%#$#?!??!
看着他一副茫然的样子，我赶快把刚才的对话在心里回放了一遍，再加上语法和拼写检查。哦，天哪！
Me: Sorry, I mean "cash back", not "trash back".
Cashier: Oh. That's all right. How much do you want?
......

打那以后，我就牢牢地分清了cash和trash这两个单词 :)