To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
The book seems duplicate. The paper quality is not so good. It is not as like as shown in the image. However,everything is well explained in this book. No doubt,It's very useful for each and everyone who want to learn French through English.