单选题 By teaming up, we finally solved the thorny problem that might ______ never have been solved by one person alone.
  • (A) solely
  • (B) fully
  • (C) further
  • (D) otherwise


【正确答案】 D
【答案解析】[理由] 空格内置otherwise后合乎语意及用法，故(D)应为正选。