A Given 是对的.你说得没错,还原成完整句应该If it had been given more attention,the tree could have grown better .但不能改为Having been given more attention,非真实条件句,当从句的主语与主句的主语相同时,...现在分词作状语中 有having done 的形态啊 如having done the homewok,I went to play footballhaving done的形式，只用在时间状语从句中。如你的这句： having done the homewok,I went to play football【俊狼猎英】团队为您解答。祝你进步。请尽快采纳。