Instruct: Classify Amazon reviews into positive or negative sentiment
Query: You could do better

This is a fine overview, but there are better products out there. I can tell from comparing this to official resources on the ETS website ([...]) that the authors don't understand ETS's question-writing strategy.There was at least one glaring editing error in a practice test which made it impossible to answer one of the questions.The tone of the answer key is repetitive and pedantic -- for example, the reminder to "Devise a plan" for every single question is not helpful.