汽水闸

例句：

1. 1. Thecar was stopped at the traffic light,and I had to wait for the trafficsignal to turn green.
   汽车在红绿灯前停下，我不得不等待交通信号灯变绿。
2. 2. The train station hasa large number of passengers waiting for theirtrains.
   火车站有大量的乘客在等待他们的火车。
3. 3. The engineer carefully checked the gasketon the steam engine, making sure itwas in good condition before starting the engine.
   工程师仔细检查了蒸汽引擎上的密封圈，确保其处于良好状态后才开始启动引擎。