If you feel confused about terms like ‘transitive’ and ‘intransitive’ verbs or ‘demonstrative’ and ‘interrogative’ pronouns, then another book to consider is Cambridge University’s English Grammar: Understanding the Basics.
Unlike the other two books above, this text explains English grammar step by step. It’s especially useful if you have to do a lot of writing in English, but also good to read if you want to reach an advanced level fast.
With the other two books, you will how to fix your mistakes and build longer sentences, but this book helps you to understand ‘the big picture’ of English.
In the excerpt below (explaining phrasal verbs), you get a ‘taste’ of how clear and simple the book is.