zài / píng tǎn / de / gāo sù gōng lù / shàng / chē liàng / huàn rù / gāo sù dǎng / hòu / fā dòng jī / zhuǎn sù / huì / yǒu suǒ / jiàng dī在平坦的高速公路上,车辆换入高速挡后,发动机转速会有所降低。On a flat highway, the engine speed will decrease somewhat after the vehicle shifts into high gear.