the great efforts we had made three years before we failed to carry our plans through.A.

问题补充：

the great efforts we had made three years before, we failed to carry our plans through.

A. While

B. Although

C. Even if

D. In spite of

答案：

A. While

B. Although

C. Even if

D. In spite of

解析：考查连词。A,B和C项只能引导句子，而the great efforts是名词词组，所以选D。