Facts showed that only when they united the strong enemies.
A. could they defeat
B. they could defeat
C. they did defeat
D. had they defeat
网友回答
(答案→)A. could they defeat
B. they could defeat
C. they did defeat
D. had they defeat
解析：考查倒装。Only谓语句首应该用部分倒装。即把情态动词、助动词等提到主语前面。排除B、C；句意“事实证明，只有当我们团结起来，他们才能抵抗强大的敌人。”故选A。