OK, so it's only a little dot, but it's big trouble if you miss one out. Start each new sentence with a capital letter. Help with capital letters English Howlers Commas You must use a comma to separate items in a list, and you should use a comma to mark short pauses in speech. Many students use commas too often, or where full stops ought to be. So prefer a full stop to a comma if you have the choice.
Many students know very little about apostrophes and their writing really shows it.
Quotation marks must be placed both at the beginning and at the end of the word or words you are using. Many students are forgetful with quotation marks. They often mark only one end of the quote, or do not mark the quote at all. Use it instead of a full stop. Many students fail to mark questions.