Question

求分析英语句子成分

People all have heart for mercy,but it is often a flashing thought across one’s mind that decides whether it is good or evil.

Answer 1

这是并列复合句。

第一分句 People all have heart for mercy （简单句）
〔主语〕people
〔同位语〕all
〔谓语动词〕have
〔宾语〕heart for mercy 【for mercy 是后置定语】

第二分句 but it is often a flashing thought across one’s mind that decides whether it is good or evil （复合句）

主句 it is often a flashing thought across one’s mind
〔主语〕it
〔谓语动词〕is
〔频度状语〕often
〔表语〕a flashing thought across one’s mind （across one’s mind 是 thought 的后置定语）

定语从句 that decides whether it is good or evil
〔关系代词兼主语〕that
〔谓语动词〕decides
〔宾语从句〕whether it is good or evil

追问

for mercy中为什么要用for?

Answer 2

学好从句之前学好句子的成分很重要。