原文：The man in a hat。

question:Why didn't Caroline  recognize the customer straight away?

I bought two expensive dictionaries here half an hour ago. But I forgot to take them with me.

Who served you,sir?

The lady who is standing behind the counter.

Which books did you buy?

The books which are on the counter.

Did you served this gentleman half an hour ago , Caroline?He says he is the man who bought these books.

I cant remember.The man who I served was wearing a hat.

Have you got a hat,sir?

Yes I have.

Would you put it on please?

All right.

Is this the man that you served ,Caroline.

Yes,I recognize him now.

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知识：

customer：顾客。

counter：柜台。

recognize：v  认识。