Demo app but still good for learning English. In this demo there is one regular English language verb with 60 forms of several verbs. I said 60 - yes, something a book could not do. For learning past, future, perfect, negative, continuous this app is fantastically good. Have fun and speak English.
In the professional version there are 620 common, modern regular verbs and each has 60 verb tense forms. In future, past perfect, simple past, continuous present, continuous future, modals - could, should, would and all the negative forms.
It is a huge collection to practice. Once you have leaned how to do them you will easily catch up with native speakers who use lots and lots of sentence structures in every day language.
This is very good for teachers of the English Language because it provides many hopurs of lessons needing no preparation.

There is no book that could do this, only a computer could provide nearly limitless (35,000) patterned sentence questions.

Once you can do all of these structures and patterns the English language will become easy to understand. Many foreign speakers of English cannot manage many of these sentence patterns, but native speakers have no problem and often try a difficult structure because it 'sounds correct' to them.

It took me a long time to write this program and I am very proud of it. As a learner you have a fantastic possibility to learn complex English easily. Hard work at first but easier later.