I was making coffee at kitchen, when my daughter came in. I said, “Would you like some coffee?”

She said, “ That would be nice if you could leave some for me.”

The tone of the sentence is going up (increasing), giving a positive/warm atmosphere in the room.

A few years ago, Prof. Brian Holton from Department of Chinese and Bilingual Studies of Hong Kong Polytechnic University once mentioned to me, that many people learned the language but the culture.

The way my girl answered is one of the example of learning the culture of Canadian English. It is a kind of instant reaction in such a relax setting, talking about such a simple stuff.

“That would be nice if you could ......” is a normal way to show appreciation when people offering you something good.

If the answer turned out to be “OK, thank you.” It is still good, but just lack of something. If it were like “That's great! Sure, I'll have some.” It is not a bad reply, but it seems too exaggerating.

Some learners just never pick it up. As a teacher, we can't say it to their faces, except speaking in a normal way again and again and hope they could get it finally.