请看下面一题：
He is _________ to win the match. Really? But I dont think so
A. easy B. difficult C. possible D. sure
【分析】此题应选D，其余三项均有可能误选，因为假若单纯从中文意思来看，其余三个答案均说得通。但问题是将A、B、C三项填入空格处均不合英语习惯。按英语习惯，easy 和difficult 后接不定式时，其主语(或逻辑主语)通常应是 it，而不能是具体的人或物，除非这个主语与其后不定式有动宾关系。如：
我做这工作很容易。
误：Im very easy to do the work.
正：It is very easy for me to do the work. (用形式主语 it 作主语)
正：The work is very easy for me to do. (主语为具体的事物，但它与其后不定式有动宾关系，即 to do the work)
我们很难准时赶到那儿。
误：We are very difficult to get there in time.
正：It is very difficult for us to get there in time. (用形式主语 it 作主语)
比较：He is very difficult to work with. 他这个人很难相处。(用具体的人作主语，但它与其后不定式具有动宾关系，即 to work with him)
有时不是用 it 作形式主语，而是用其作形式宾语。如：
We found it easy to do the work. 我们发现做这工作很容易。
但是不说：We found him easy to do work.
至于，possible 后接不定式时，其主语只能是 it，不能是具体的人或事物，即使该主语与其后的不定式有动宾关系也不可以。如：
我们有可能会找到一些更便宜的。
误：We are possible to find some cheaper ones.
误：Some cheaper ones are possible for us to find.
正：It is possible for us to find some cheaper ones.
有时不是用 it 作形式主语，而是用其作形式宾语。如：
We found it possible for him to do the work. 我们发现他可能做那工作。
但不说：We found him possible to do the work.