There is a lot of problems to settle 还是to be settled?为什么有的地方是 to be done ,有的地方是to do 怎么区分?

There is a lot of problems to settle 还是to be settled?
为什么有的地方是 to be done ,有的地方是to do 怎么区分?

首先.不是there is...应该there are吧.
应该是to be settled.
it has to be done
it's a long way to go
应该是判断事物的状态.如果要达到某种状态就用to be done
个人猜想.其实大多数时候都是靠语感做这种题额