One day, I happened to meet an Englishman in a store and soon we began to talk. As I was talking about how I was studying English, the foreigner seemed to be very surprised, gently shaking his head and saying, "You don't say! You don't say!" I was puzzled(困惑的), and I thought, "Perhaps this is not a right thing to talk about. " So I said to him, "Well, shall we talk about the Great Wall? Have you ever been there?

"Certainly. When I'm back home, everyone will laugh at me if I leave here without seeing it. The Great Wall is wonderful!" he answered.

"Yes, it is one of the wonders in the world. And people from all over the world have come to visit it, " I added. As 1 was telling him more about it, he said again, "You don't say1"

I couldn't help asking, "Why do you ask me not to talk about it?"

"Well, I didn't ask you to do so, " he answered, greatly surprised.

"Didn't you say "You don't say!'?" I asked again.

Hearing this, the foreigner laughed loudly. He began to explain. You don't say!'means' Really?". Perhaps you know little about English idioms（习惯用语)"

Wow! How foolish I was! Since then I have been careful with English idioms.