I believe this to be a "grammar myth." In my answer in this thread http://www.italki.com/question/247085 I give examples of sentences starting with the word "but," written by great English authors--including Melville, Dickens, Addison and Steele, Shakespeare, and the King James version of the Bible. "The Economist" is a good example of well-written modern English. If it's good enough for the copy editors of "The Economist," it should be good enough for everyone. But you can't fight grammar myths, so if your writing is going to be judged by an English teacher, it is best to carefully avoid ever splitting an infinitive, beginning a sentence with a conjunction, or using a preposition to end a sentence with.

Yes, some teachers will insist that you cannot start a sentence with a conjunction, such as 'for', 'and', 'not', 'but', 'or', 'yet', 'so' (FANBOYS), 'however,' etc... But the truth is that you can start a sentence with a conjunction. And it is not starting a sentence with a conjunction that makes a sentence "feel" informal or even "impolite," but the entire sentence *and* context. See: http://www.dailywritingtips.com/can-you-start-sentences-with-%E2%80%9Cand%E2%80%9D-and-%E2%80%9Cbut%E2%80%9D/ http://www.gpuss.co.uk/english_usage/start_sentence_conjunction.htm

That's a great question. In speech and casual writing, there's no problem at all with starting a sentence with the word "but." In more formal writing (especially for class or if you're trying to impress somebody), you should avoid beginning a sentence with but.

I agree with you and my fellow countrymen. The rule about not starting a sentence with a conjuction is utter nonsense, imposed on innocent schoolchildren by "teachers" who couldn't make it in the real world. But if you absolutely have to avoid antagonizing the grammar nerds, you can always use something like "on the other hand," "otherwise," "be that as it may," "nevertheless," etc. And congratulations to you, Kailin, for paying attention and discovering the truth, instead of just believing what some self-appointed grammar police claim.