一等的学习:自己教育自己二等的学习:朋友互相砥砺三等的学习:等着老师教导劣等的学习:拒绝所有言教。

• The first-rate learning is self-motivated. The second-rate learning comes of the encouragement of friends. The third-rate learning waits for the right teacher. The fourth-rate learning rejects all schooling.