Having a solid grammatical base is one of the cornerstones to great teaching. Unfortunately, so many TEFL/CELTA courses hardly cover language awareness at all. If you want to teach well, you have to have to know the ins and outs of English grammar. What’s the structure of the Present Perfect Simple and can you name three functions? What is the difference between would and used to? What are the different categories of State Verbs? Most native English speakers would not be able to answer one of these questions.