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

问题补充：

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

A. I did find

B. did I find

C. I’ve found

D. have I found

答案：

A. I did find

(答案→)B. did I find

C. I’ve found

D. have I found

解析：句意：发现解决这个问题如此困难，所以我答应向汤姆咨询一下。So位于句首，应使用部分倒装。另外本句用过去时态。