闸门

例句：

1. 1. The gateway to the new library is just a few steps away.
   通往新图书馆的入口就在几步之遥。
2. 2. The gatekeepers were responsible for opening and closing the gates.
   看门人负责开关大门。
3. 3. The river's flow was controlled by the gates at the bridge.
   河流的流向由桥上的闸门控制。