陈豪在北京的ABC美国公司工作，他看见美国同事Amy正跟办公室另外几个人一起出去。
(Office ambience)
CH：Amy, Are you guys going to lunch?
A：Yes. Would you like to join us?
C：好啊。我跟你们一起去。
A：I have to make one phone call before I leave. Would you like to wait for me or go ahead with everyone else?
C：我等你。
A：Thank you.
C：No problem.
A：Say, Chen Hao, my phone call can wait a few minutes. I need to tell you something while it is on my mind.
C：Uh-oh. 我做错什么事了吗？
A：No, you said something wrong. Actually you said two things that caught my attention.
C：嗯....可我刚才没说什么啊？
A：First, you used the expression "You guys."
C：我那些同事经常把you guys挂在嘴边上，我这可是跟美国人学的。
A：I know they do, but that doesn't mean it's correct or polite.
C：为什么不对呢？
A：Because the word "guy" is an informal term that refers to a man or boy. People today use the plural "guys" without regard for gender. That is not correct usage of the word and it demonstrates a lack of polish.
C：那要是有男有女应该怎么说呢？
A：You could have simply asked, "Are you going to lunch?" Or you could have said, "Are you ALL going to lunch?"
C：我知道了。
A：Now please excuse me while I make that quick phone call. Otherwise we'll miss lunch altogether.
C：No problem.
******
Amy打完电话跟陈豪一起去吃午饭。
C：Amy, 你刚才不是还要纠正我另外一个错误吗？
A：Yes. I have noticed that when someone says "thank you", your response is always "no problem."
C：我经常听别人这么说啊，难道这也不对吗？
A：Lots of people say that in response to "thank you." However, that is not the correct reply. The correct response to "thank you" is "You are welcome."
C：Amy, 你是不是太挑剔了？
A：No, it's being polite and polished. "You guys" and "no problem" are slang phrases which are not formal.
C：俚语？
A：That's right. Slang expressions will detract from your professional image. "You guys" is only acceptable with a group of men in a very informal setting like the locker room.
C：那"no problem"呢？
A：It is only acceptable when someone asks if you have problem with something.
C：我明白了，就是说一定要注意区分俚语和正规语言，特别是不能在正式场合乱用俚语。
A：You got it! Now let's eat. I am starving.