An invaluable, entertaining and information-packed A to Z guide that answers all those questions you might hear one person asking another in an office, such as: Is it 'a hotel' or 'an hotel'? What are split infinitives, and should you avoid them? Do you know when to use 'that' or 'which'? Is a semi-colon like a comma? When do you use a colon? It's website? Its website? Where do y…