考查as引导的让步状语从句。as可引导让步状语从句，表示“虽然，尽管”，但要用部分倒装结构，形式如下：①形容词＋as＋主语＋系动词。如：Tired as he is，he offers to help me.②过去分词＋as＋主语＋系动词。如：Well-written as the book is，the author is not satisfied and prepared to revise it.③名词＋as＋主语＋系动词。如：Student as he is，he does not study hard.④副词＋as＋主语＋谓语部分。如：Much as I admire his courage，I don't think he acted wisely.⑤动词原形＋as＋主语＋谓语的另一部分（情态动词或助动词may，might，will，would等）。如：Try as you will，you won't be able to persuade him.所以，根据句意，选D。  

【参考译文】尽管她尽力了，苏还是打不开这门。