—Here you are at last! What kept you so long?—Sorry I’m late. But do you know what great

问题补充：

—Here you are at last! What kept you so long?

—Sorry, I’m late. But do you know what great difficulty I have your house.

A. found

B. finding

C. to find

D. for finding

答案：

A. found

(答案→)B. finding

C. to find

D. for finding

解析：句意:--你终于来了，什么事使你用这么长的时间？--对不起，我来晚了，但是你知道我找到你的家有多困难。这里是感叹句型，被感叹的是名词difficulty，所以用的是what，这里是短语have difficulty （in）doing，in可以省略，故选B。