It's uncertain _____the experiment is worth doing.能用if吗!又说whether可以的!到底选哪个?

问题描述:

It's uncertain _____the experiment is worth doing.能用if吗!又说whether可以的!到底选哪个?
我想问个清楚!网上有的说if可以引导主语从句,有的又说不能,我想要个正确的答案!到底能不能!如果能的话下面这道题应该怎么做!
It's uncertain _____the experiment is worth doing.
A.if B .that C.whether D.how

uncertain表示否定所以不能用if.句子最后省略了or not