借题发挥

Explanation: By the subject to do something for the article, to express their true opinions or ideas. Also refers to the ground under the guise of something, to do other things. 　　Usage: Partial official; as predicate, object, attribute, adverbial; 　　Source: Wang Heng, "Yu round gown" second off: "I followed the partition will stop a few programs, this was originally an ulterior motive." 　　Examples: Although the ~, but by the wrong title, my way of Wang Yunsheng, is still admirable. ★ Guo, "Don Quixote as a modern way." Thesaurus:  use the past to disparage the present, Zhijimagou, The old days, make the past serve the present, Curse that dog pig, Yigufengjin, The ancient metaphor for the modern, Old were Kam, cite past and prove today, By the ancient metaphor for the modern