请问:what is harder to establish is whether …….怎么翻译,里面的to establish 是什么成分?先谢谢了
原句是：what is harder to establish is whether the productivity revolution that businessmen assume they are presiding over is for real.
怎么翻译,里面的to establish 是什么成分?
有人可以帮帮忙吗,谢谢了.