semilunar notch

例句：

1. 1. The car's engine compartment has a semilunar notch for the air filter.
   汽车的发动机舱有一个半圆形凹槽用于安装空气过滤器。
2. 2.The mountain range is characterized by its semilunar notches and steep slopes.
   这座山脉以其半圆形凹槽和陡峭的坡度而闻名。
3. 3.The artist used a semilunar notch to create a seamless transition between the two pieces of artwork.
   艺术家使用半圆形凹槽来在两件艺术作品之间创造无缝过渡。