The part we are looking for is "career". In the context provided, the question seems to emphasize the importance of understanding the lesson during class explanations, which helps in solving homework assignments and exams easily. Teachers usually focus on key questions that are crucial for assignments and tests. By preparing in advance and actively participating in class discussions, students can enhance their understanding of the subject matter and excel in their academic performance. The answer "career" suggests that focusing on one's career development and planning is essential for academic success and future growth.