为了应对比赛的最后阶段，运动员们决定加快节奏。

The athletes decided to ___upshift their pace for the final stage of the race.

当车速加快时，你应该升档以保持引擎平稳运转。

You should ___upshift when the car speeds up to keep the engine running smoothly.

升级后的系统将显著提升我们的工作效率。

The upgraded system will ___enhance our work efficiency significantly.