Tact to deal with classroom teaching in an accident, or to capitalize on the trend is real, or forward, or deceitful act, subtly shift the topic, from the current dilemma.

机智地处理课堂教学中的偶发事件，实质就是或因势利导，或抛砖引玉，或移花接木，巧妙地把话题转移，摆脱眼前的窘境。