Do I need to know all of English Grammar before I can teach ? 1. You don’t need to know all the grammar of English in order to teach it. 2. What you do need to have are some tools, some approaches, that will enable you and your Ss to discover more about and work usefully with grammar. 3. The best way to learn about something is to try and teach it ! You will learn about grammar as you teach. The more you prepare your lesson and teach them, the more you’ll find you’re comfortable with it.