Question

I find these problems are easy ________．

1. A.
   to be worked out
2. B.
   to work out
3. C.
   to work them out
4. D.
   to be worked them out

Answer 1

B
名词(代词)+be+adj．(easy difficult, fit)+to do sth．结构中，尽管句中的主语是动作的承受者，不定式在意义上表被动，形式上却是主动。这时可以看成是省略了的逻辑主语for us, for me, for you等。