Grammar Express - Degrees helps you master the use of expressions in writing English. It contains over 26 pages of lessons explaining how to change a sentence from one grammatical form into another without changing its meaning. It's a valuable exercise, for it teaches you how to introduce variety in writing English.
You can learn the grammar rules, study the examples and test their understanding by taking quizzes. At the end of the quiz the user is presented with a test summary and the explanation for each test question.