Good It is really good for younger students
It's really good and easy
Not ok for UK English We sat have/become not gotten.
Very nice Good app so anyone red
That is great! But it needs... The app is the best one I've ever used. But there is a problem. When we enter a correct answer in practice mode, the answer get disappeared! It is better to have chance to have a look at the correct answer to keep it in mind and then go to the next test.
The official English Grammar in Use app, written by Raymond Murphy.