请派援军来——敌人在大举进攻了。

Send for reinforcements - the enemy are attacking in strength.

这支巡逻队几乎被包围了，正在危急之际，援军赶到了。

The patrol was almost surrounded and then, at the eleventh hour, reinforcements arrived.

当德国人最终意识到盟军的作战意图时，已经来不及组织援军反扑了。

When the Germans were clear of the real intention of the Allies at last, it was too late to organize reinforcements.