No but's! "But!.." the first man said. "No but's!" said the second man, shaking his head. "To put it simply Charlie, no but's!". "But why?!" said Charlie. "Why can't I say but.." "No but's I said" yelled the second man again, cutting Charlie off mid-sentence. Charlie shuffled his feet on the pavement and started to whistle as silence overcame the two men. "Okay Charlie I'll explain it one more time..." said the second man. "You should not, can not and will not use the word but at the beginning of a sentence. It's just not done. Proper people just don't do such a thing." Charlie turned as if to go then grinned back at his friend and said; "So who made you an English teacher anyway?" Actually but can be used at the beginning of a sentence. Interesting page: http://grammar.about.com/od/grammarfaq/f/butsentencefaq.htm