both sides accept these terms will everlasting peace be established in this region. A. Un

问题补充：

both sides accept these terms will everlasting peace be established in this region.

A. Unless

B. As long as

C. If only

D. Only if

答案：

A. Unless

B. As long as

C. If only

(答案→)D. Only if

解析：Only+状语位于句首主句要倒装。A. Unless除非 B. As long as 只要 C. If only 如果…就好了 D. Only if 只有…句意：只有双方接受这些条款永久的和平才能在此地区实现。 选D