1. The advantage of textbook help is that it covers all the knowledge points of the textbook, and the knowledge is explained step by step, from shallow to deep, and each knowledge point is explained comprehensively and meticulously. The disadvantage is that students are too dependent after reading it.

2. the advantage of 2.nudge is four-color printing, high face value, interesting comics and outstanding difficulty. The disadvantage is that nudge may not be able to give a comprehensive answer to complex questions, which requires learners to study further.