These examples, once to his article, will make it sound more reasonable and acceptable.
A. add
B. to add
C. adding
D. added
网友回答
A. add
B. to add
C. adding
(答案→)D. added
解析：考查状语从句的省略式：句意：这些例子一旦被加入到他的文章中，就可以使它听起来合理能让人接受。当主从句的主语一致的时候，可以省略从句的主语和be动词，这句话完整的是These examples, once they are added to his article, will make it sound more reasonable and acceptable.省略主语和be动词后，就是Once added。选D。