面对失败，他加倍努力训练以提高成绩。

Facing failure, he ___redoubled his training efforts to improve performance.

面对竞争对手的挑战，他们加倍努力提升产品质量。

Facing competition, they ___redoubled their efforts to improve product quality.

在扑克游戏中，他信心十足，决定再次加注。

In the poker game, he felt confident and decided to ___redouble his bet.