He was also always ready to call on students to give impromptu answers, to deepen everybody's impression. If somebody dared to misbehave, he had better be prepared to duck flying chalk or go up on the platform to solve a problem.
他並隨時點學生起來一問一答，加深大家的印象，如果還有人「膽敢」作怪不專心，得隨時準備「吃」粉筆頭，或「趴」黑板解習題了。