Though there is virtually no limit to the number and kind of mistakes a student can make when learning the English language, the errors presented in this book have been carefully selected on the basis of three criteria. The first is how frequently the errors are made by the majority of English language students (at least until they reach fluency level); the second is the relevance and frequency of these words and structures in everyday English; and third, how badly the errors sound to a native speaker. If you want to sound like you have an acceptable domination of the English language, you must avoid committing these mistakes.