The apostrophe.

Apparently, one of the most misused and misunderstood punctuation marks is the apostrophe. Don't know why - it's pretty straight-forward. The apostrophe has two uses - to indicate that some letters are missing, and, in the apostrophe-s usage, to indicate possession. Words like can't, don't, they're, are all examples of the first usage. The apostrophe indicates where the missing letter is. It can of course be more than one letter - "I'll think about it", for example, where the apostrophe indicates the omission of "wi". And then pedants like me will write 'phone, rather than phone - the apostrophe indicating the missing "tele". Possession is indicated by apostrophe-s, so Mary's book, the child's toy, Dragon's Den and so on. Just one exception and one problem - the exception is "it's / its" - with the apostrophe it is a contraction of "it is" and without, it means "belonging to it" - so no apostrophe even though it's possessive. You just need to learn that one. And then the problem - what do you do if the name of the possessor already ends in "s"? The book belonging to James, for example, or the office of the boss, or a school for boys? The convention (and it seems to be no more than that) is that you follow the pronunciation - if, when spoken, you add an extra "siss" syllable, then you write it as s-apostrophe-s, otherwise its s-apostrophe. So it's James's book, the boss's office, but a boys' school. Simple isn't it - or perhaps not, as so many people seem to get it wrong. Perhaps I'll come back to this later, and have a look at what has become known as the "Greengrocer's apostrophe".