Today we have on the test an application for iPhone from the “Education” category, which will be extremely useful not only for schoolchildren and students who study English, but also for everyone who wants to improve their knowledge of the English language from basic ones. The advanced English course from the Dmitry Petrov Center is available for both iPhone and iPad and is called Dmitry Petrov's Polyglot 16. This application is official and is designed to improve basic knowledge of English according to Dmitry Petrov's method. 
Lessons are grouped by topic, there are 16 of them in the appendix:
- Third form of the verb
- State designation
- Present Perfect Time
- Time alignment
- Complex addition
- Modal verbs
- Conditional sentences
- Cases of using the infinitive
- Verbs with similar meanings
- Gerundii etc.
The information is presented in a very simple and accessible way, for each rule a clear example is given, so that mastering the lessons will not be difficult for either a schoolchild, or students, or even elderly people. To consolidate knowledge, after each lesson, it is proposed to take a test, the results of which will demonstrate the quality of the acquired knowledge. It will not be superfluous to show off your successes in the Gema Center, the application has a bonus system and a board of honor, and the better you pass the tests, the more rewards you get. The results can please your self-esteem. 
Each of the 16 lessons is grouped by content into separate chapters, if you did not have time to study the whole lesson at a time, you can always return to the table of contents and return to the place where you stopped. In order to go through the lesson again, with one tap, you can reset the lesson statistics and start again. 
If you are ready for the sprint challenge, all training included in the application can be completed at once, for this there is a separate section “General training” in Polyglot. If you like to compete with time, there is a separate “Blitz-training” mode for you, in which you will need to give the maximum number of correct answers in the allotted time. 
For your achievements, there is a separate page on which your result, a board of honor and awards will be displayed. There are no complaints about the application interface, it is as simple as possible, which is typical for this category of software. All buttons and graphics are labeled and intuitive. The text of the lessons is easy to read, headings are highlighted in a separate color, important information is underlined in bold. I did not find the ability to change the font size and color of the headings, but is it necessary? I hasten to draw your attention to the fact that the application does not carry annoying advertising, but for the information provided, you will need to pay 279 rubles one-time. It would be unfair to judge the developer for this, because the technique is unique in its own way. Whether it is expensive or not, let everyone decide for himself. The cumulative rating of the app in App Store is almost a full 5 stars, which is important.