高等继续教育 / 英语语法
正确率：100%
题型描述: 单选题
So difficult ＿＿＿＿＿＿ it to work out the problem that I decided to ask Tom for advice.
A.I have found
B.I did find
C.have I found
D.did I find
So difficult ＿＿＿＿＿＿ it to work out the problem that I decided to ask Tom for advice.
A.I have found
B.I did find
C.have I found
D.did I find
参考答案：