1. The walls of the castle were crenelated to provide better defense against enemies.

城堡的城墙上开设了垛口，以提供更好的防御。

2. The architects decided to crenelate the roof of the building to give it a unique and medieval look.

建筑设计师决定在建筑物的屋顶上开设垛口，以赋予它独特而中世纪的风貌。