semi-circular arch

例句：

1. 1. The arch was designed to protect the bridge from floods.
   这座拱门的设计是为了保护桥梁免受洪水侵袭。
2. 2.The archway is a symbol of the city's rich history.
   这个拱门是这座城市丰富历史的象征。
3. 3. The arch was built during the Roman era and still stands today.
   这座拱门建于罗马时期，至今仍屹立不倒。