Unit 4 was all about grammar. The Unit was quite easy for me, because I have learned all of the rules before I started with this course. To quickly summarize this Unit: The rules for the present simple and present continuous were given together with usage examples. After that the same was done for the present perfect and present perfect continuous. Examples of common student mistakes were given and teaching methods for each tense were provided as well. I think It was good for me to review these grammar rules and I am looking forward to the next Unit.