So difficult it to work out the problem that I decided to ask Tom for advice.A. I did fin

问题补充：

So difficult it to work out the problem that I decided to ask Tom for advice.

A. I did find

B. did I find

C. I have found

D. have I found

答案：

A. I did find

(答案→)B. did I find

C. I have found

D. have I found

解析：以so＋adj./adv.开头的句子要在主句中进行部分倒装。句意：我发现这个问题是那么的难，就问了汤姆。