Question

The machine has been made easier for it __________.

A to operate. B. operated. C. being operated. D. To be operated
为什么是D呢？。be+ adj. +to do. 并且主动表被动，吗？

Answer 1

这样理解比较简单：

1。 The machine is easy to operate.
2。 The machine has been made easier for it (指machine。。。是被操作的) to be operated （被动）
3。 The machine has been made easier for people （人。。。操作） to operate.。。。（主动）

Answer 2

be+ adj. +to be done不定式的被动结构 这个机器被制造，操作起来很简单。

追问

那这种形式什么时候是主动表被动呢？

追答

It's important to learn English well .学好英语很重要。这种形式应该算吧。