This app is a comprehensive English grammar book for learners of English.

The lessons are organized by topic and are accompanied by an extensive set of questions. Each question is composed of a title, a sentence, and an answer. The answer is usually presented in the form of a sentence.

The app is intended to be used as a learning tool. The user can review each lesson and each question.

The app includes a comprehensive list of topics and sub-topics. Each subtopic is composed of a number of lessons and questions.

The user can access the app from any device and can study at any time of the day.