士兵们在河对岸建立了一个桥头堡，为后续进攻做准备。

The soldiers secured a ___bridgehead across the river to prepare for the upcoming attack.

这家初创企业在亚洲市场的早期成功为未来的扩张奠定了桥头堡。

The startup's early success in the Asian market established a ___bridgehead for future expansion.