求救!英语语法填空It is no good ______（learn）strings of words and lists of grammatical rules.横线内应该填什么?为什么不填to learn

learning
译文：学习一堆词汇和语法规则没有好处.
表语是no use,not any use,not the slightest use,no good,not much good,fun等时,常用动名词（不用不定式）做主语并后置,用 it 做形式主语.
例如:It’s no use crying over spilt milk.