Question

He thought nobody was around , but he was in fact seen______into the office building.

1. A.
   to steal
2. B.
   steal
3. C.
   stole
4. D.
   stolen

Answer 1

A
考查非谓语动词。句意：他认为周围没有人，但是实际上有人看到他进入大楼偷东西了。See后面接不带to的不定式，但是当变成被动语态时，后面要加上to，故选A。