关于being done

题目

关于being done
the problem which is being discussed is important.
这句话中的being是起到什么作用?定语是个什么结构?
为什么定语里有两个be?

答案

　　is being done是被动语态的现在进行时形式,意思是正在被做.which is being discussed是定语从句,修饰the problem.
　　The problem which is being discussed is important.
　　翻译：正在被讨论的哪个问题非常重要.