题目内容：

I will let you know if anything comes __(up.about).选哪个,为什么?

优质解答

come up 的意思是长出,上升,升职等；如：The snowdrops are just beginning to come up.雪花莲刚刚开始长出地面.
come about指的是发生.
如：how did this come about?这是怎么发生的?
所以是about,