亲:以so+形容词/副词提前的句子要用倒装句结构。即:助动词/情态动词在前,主语在后,然后动词。所以填B。祝你学习进步!望采纳,谢谢!
首先还原句子:I felt it is so difficult to live in an English-speaking country that l determined to learn English well这是过去时,所以排除AB然后看到给出的题目是一个so +adj 的前置倒装,所以用did I felt,选D
D望采纳,谢谢