It can’t write you anything that hasn’t been written a million times before, but it can give you a paragraph and tell you to find the verbs, and then mark the exercise to a shocking level of accuracy. It can explain what you did wrong and give accurate examples and details. Then you can say “I don’t get it…I still don’t get it” a hundred times and it will try and try to explain it to you, endlessly, and it will never get frustrated or impatient.