It is exciting for us to have a picnic in spring的考点

问题描述:

It is exciting for us to have a picnic in spring的考点

it 作形式主语的用法
动词不定式的复合结构(for sb to do sth ) 作主语
 
如不明白请追问还有一个:He always goes swimming on hot summer days,but he can't swim well.的考点go doing sth 常用于“去从事一些体育, 娱乐活动”再如:go dancing/ hunting/ climbing/ skating/ boating...