杏仁孔

例句：

1. 1. The oak tree is one of the oldest known species in the world.
   橡树是世界上最古老的已知物种之一。
2. 2. The acorns are small and round, with a hard outer shell.
   橡子小而圆，外壳硬。
3. 3. The acorns are often used as food for animals, especially deer.
   橡子经常被用作动物的食物，尤其是鹿。