If you redouble your efforts, you try much harder to achieve something. If something redoubles, it increases in volume or intensity.
例句
The president also called on nations to redouble their efforts to negotiate an international trade agreement...总统还呼吁各国就签订国际贸易协定加倍努力进行磋商。The applause redoubled.掌声加倍热烈。
英汉词典释义
vt. & vi.
进一步加强,大大增加
We redouble our efforts for Manhan’s release.为了解救马汉,我们做了最大的努力。
vi.
再加倍,翻两番
英英词典释义
Verb
1. double in magnitude, extent, or intensity;
"The enemy redoubled their screaming on the radio"