Hi Christopher. It depends on whether you're using 'such as' in a defining or non-defining relative clause. (I've put the grammatical terminology in here in case you want to look it up, but I'll give you some examples and you can ignore the terminology if it's easier for now). Wild cats such as lions and tigers live mainly in the wild. (No comma, because I am describing exactly the wild cats I'm talking about). Wild cats, such as lions and tigers, live mainly in the wild. (Commas, because this is EXTRA INFORMATION. I could take it out and it would make no difference to the information I am giving you. (Wild cats live in the wild). Let me give you an example without 'such as', which might make it clearer. My brother who lives in America is 42. (I'm describing 'my brother who lives in America'. All this information is necessary and I can't take any of it out. I have a brother who lives in Ireland, one who lives in Australia and one who lives in Peru. So 'my brother who lives in America' tells you which one I mean). My brother, who lives in America, is 42. (Here the information is EXTRA. I have one brother. I could simply say 'my brother is 42', but I choose to give you extra information (he lives in America). Therefore I need commas to separate it. It's the same rule when using 'such as'. Use a comma if it's extra information. Don't use a comma if it's vital information. I know this takes practice to learn, but good luck with it.

Hi, The use of a comma with "such as" depends on whether it is introducing an essential or nonessential clause. If it is an essential clause you don't need a comma. If you are unsure about clauses then there is a good website here which explains them : http://www.chompchomp.com/terms/essentialclause.htm