The main purpose of English Grammar Exercises by Difficulty Series is to provide you a valuable and enlightening collection of English Grammar multiple-choice grammar exercises with answer key. This book contains different items sorted by difficulty and takes you on a beautiful journey towards improving your English language skills. Within this book you can find exercises regarding a multitude of topics like: word order, articles, verb tenses, active and passive voice, phrasal verbs, pronouns, adjectives, adverbs, relative clauses, prepositions, nouns, conditionals, reported speech, confusing words, word formation and many more... There are three levels of difficulty in this book: Elementary, Intermediate, Advanced. Choose the best that suits you and enhance your English by solving the exercises. This book is the fourth book of "English Grammar Exercises by Difficulty" series. It contains 2440 exercises with answers for all English levels: 1300 for Elementary level, 570 for Intermediate level and 570 for Advanced level.