颅骨

例句：

1. 1. The skull is the first thing you see when you open your eyes.
   当你睁开眼睛时，首先看到的是颅骨。
2. 2. Scientists are studying the structure of human skulls to learn more about human evolution.
   科学家正在研究人类颅骨的结构，以更好地了解人类的进化。
3. 3. The skull was found in a cave near the river.
   颅骨在靠近河流的山洞里被发现。