Common Mistakes at IELTS Intermediate (Toloo) Mistakes (especially in the beginning) when learning a foreign language are part of the language. We can reduce errors by studying our target language further. In the IELTS test, using the correct language is a strength for candidates because one of the most important IELTS criteria is the use of error-free language. One good resource that can help learners achieve this is the Common Mistakes at IELTS book series, published in both intermediate and advanced levels. In these books, the method of teaching correcting common mistakes in English is such that often a number of sentences are presented in the form of a few correct and incorrect questions, and then the relevant point is explained in detail. Finally, students are given a number of exercises to better fit the content for language learners. Answer key All exercises are also placed at the end of the book.