how life began on earth is one of thow life began on earth is one of the biggest puzzles that scientists found hard
网友回答
选Ahow life began on earth 是how引导的主语从句
is谓语one of the biggest puzzles 宾语
that scientists found hard to solve 是that引导的定语从句,修饰宾语.其中：
that在定语从句中做的是宾语,这就是sb.find sth.+ adj.+ to do sth,的一个句型.
======以下答案可供参考======
供参考答案1:
不用分析成分了…find sb to do sth 固定用法
供参考答案2:
to do 形式表目的，我是这么理解的。