Did you know that the plural of "sheep" is "sheep" (not "sheeps")?
Some mistakes in English are incredibly common, even among advanced learners: irregular plurals, using "have done" instead of "did," incorrect prepositions ("arrive to" instead of "arrive at"), placing commas where they shouldn't be and omitting them when they are necessary... This book will teach you how to avoid some of the most common grammar and vocabulary mistakes English learners make.
If you are interested in the most common pronunciation mistakes, the author of the book has written a separate book on the topic entitled
Improve your English pronunciation and learn over 500 commonly mispronounced words.