The aim of this section is to cover some of the basic mistakes people make but especially the things I find harder to remember. This is not some kind of complete guide to English Grammar!
Right, we need to understand these in order to understand using apostrophes and hence the correct use of its and it's. A pronoun is something that can be used instead of a noun, so you can use "he" instead of "Geoff", for example. Other pronouns are as follows: I, you, he, she, they, it. Refer to pronoun (personal) for examples including an explanation of the First, Second and Third Person.
When you want to say something belongs to something, you add an apostrophe and a letter s. However there are exceptions, as usual! So the following logic should help.
Now in general to make something plural, you just add an s on the end, "the cars are made by Volvo", for example.
So, as above we know the word it is a pronoun. Also the apostrophe is used when words are used in their "belonging" form or when there is a letter missing. So the only possible uses are as follows:
There are times when you need to write in the "third person" for formal documents for example. Well the "first person" is when "I" and "we" are used, talking about yourself and what you did. The "second person" is when the word "you" is used frequently. Finaly the "third person" is where "he", "she, "they" and "it" are used and not "I", "we" or "you". This use of the first, second or third person is sometimes known as the narrative mode.