【Whatwasitaboutsnailsthatmadethewritercollectthemforhisfriendonthatdayinparticular这句话怎么翻译啊,还有结构能帮忙分析一下,比如这里的it是指什么?】

　　Whatwasitaboutsnailsthatmadethewritercollectthemforhisfriendonthatdayinparticular

　　这句话怎么翻译啊,还有结构能帮忙分析一下,比如这里的it是指什么?