half angle of entrance

例句：

1. 1.The half angle of the door is perfect for hiding things behind it.
   这个门的半角非常适合藏东西。
2. 2. The engineer measured the half angle of the roof to ensure its stability.
   工程师测量了屋顶的半角，以确保其稳定性。
3. 3. The half angle of the window allows more natural light into the room.
   窗户的半角让更多的自然光进入房间。