英语翻译We maintain that healthy skepticism about the screening

英语翻译We maintain that healthy skepticism about the screening program of cancer that's built on inconclusive data on whether or not we are helping more men than we're hurting.我知道此句话中的skepticism 接了about这个介词,而后面的 on whether or not we are...中的on 前面接的是哪个名词?是data?还是skepticism?有一名词在一句话中接两个介词这种用法吗?希望能给出正确解释!