A great list compiled and written by Misty Adoniou:
1. You can’t start a sentence with a conjunction
Let’s start with the grammatical sin I have already committed in this article. You can’t start a sentence with a conjunction.
Obviously you can, because I did. And I expect I will do it again before the end of this article. There, I knew I would!
Those who say it is always incorrect to start a sentence with a conjunction, like “and” or “but”, sit in the prescriptivist camp.
However, according to the descriptivists, at this point in our linguistic history, it is fine to start a sentence with a conjunction in an op-ed article like this, or in a novel or a poem.
It is less acceptable to start a sentence with a conjunction in an academic journal article, or in an essay for my son’s high school economics teacher, as it turns out.
But times are changing.
2. You can’t end a sentence with a preposition
Well, in Latin you can’t. In English you can, and we do all the time.
Admittedly a lot of the younger generation don’t even know what a preposition is, so this rule is already obsolete. But let’s have a look at it anyway, for old time’s sake.
According to this rule, it is wrong to say “Who did you go to the movies with?”
Instead, the prescriptivists would have me say “With whom did you go to the movies?”
I’m saving that structure for when I’m making polite chat with the Queen on my next visit to the palace.
That’s not a sarcastic comment, just a fanciful one. I’m glad I know how to structure my sentences for different audiences. It is a powerful tool. It means I usually feel comfortable in whatever social circumstances I find myself in, and I can change my writing style according to purpose and audience.
That is why we should teach grammar in schools. We need to give our children a full repertoire of language so that they can make grammatical choices that will allow them to speak and write for a wide range of audiences.