问题
选择题
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
答案
答案：A
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。