to change gear

例句：

1. 1.We need to change our speed to match the traffic.
   我们需要换挡以适应交通流量。
2. 2.The car's engine is sound, but it needs to change gear for better acceleration.
   汽车的引擎是好的，但它需要换挡以便更好的加速。
3. 3. When driving on a hill, we must change gear to avoid stalling.
   在上坡时，我们必须换挡以避免熄火。