The book represents a wonderful love story, so once , it will be popular with young people.
A. publishes
B. publishing
C. published
D. having published
网友回答
A. publishes
B. publishing
(答案→)C. published
D. having published
解析： once作为连接词引导条件状语从句, 后面可以接现在分词或过去分词,由于it与publish为被动关系, 所以用过去分词published作状语。