When I opened the door I was surprised Bruce standing outside the door.A. seeingB. sawC.

问题补充：

When I opened the door, I was surprised Bruce standing outside the door.

A. seeing

B. saw

C. see

D. to see

答案：

A. seeing

B. saw

C. see

(答案→)D. to see

解析：此题考查固定句型结构be surprised to do sth表示惊奇的去做某事，故选D。