So difficult it to live in an English-speaking country that I determined to learn English.
A. I have felt
B. have I felt
C. I did feel
D. did I feel
网友回答
A. I have felt
B. have I felt
C. I did feel
(答案→)D. did I feel
解析：以“So+ 形容词”开头的句子要用部分倒装；由determined可知用一般过去时。