Because he was nervous in high school, he would know self-discipline. When he goes to college, the requirements of college courses may not be too strict, so he neglected his studies and may not be very self-disciplined in his studies.

Self-discipline means that in the absence of on-site supervision, you can change passivity into initiative by asking yourself and answering questions, consciously abide by statutes, and restrain your words and deeds with usage.