Staring at the teacher's mouth and hands in class, thinking always keeps up with the teacher's thinking, without distractions.

Finish your homework yourself

Try to finish your homework after class, and then check that it is correct before you can answer questions with students with good academic performance, exchange ideas on solving problems, and try not to ask stupid questions.

Understand what you have learned and apply what you have learned.

Personal advice is not to memorize the concept of endorsement, but to understand and apply what you have learned.