题目内容：
请在第__30__处填上正确答案。
A．It goes like this,"A man without a smiling face must not open a shop. " B．As luck would have it,she sat down next to a gentleman who was more than a little distraught about the long wait for service.
C．Just what you and I would do,of course；he smiled back at the baby.
D．No one was talking to anyone else, and all were probably thinking of a dozen other things they would rather be doing than"wasting time" sitting in that office.
E．Your smile brightens the lives of all who see it.
F．So naturally we are glad to see them.
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