英语语法分析

The Protoceratops had a frill on its head.

原角龙的头上有一个褶边。

The Protoceratops had a frill on its head. Males had a bigger frill than females.

龙 的头上长着个褶边一样的装饰，雄性的比雌性的大些。

The Protoceratops was a vegetable-eating dinosaur about the size of a sheep that experts believe lived in herds during the Cretaceous Period.

原角龙是一种食草恐龙，体型和绵阳差不多大小。专家们都认为他们曾在白垩纪时期过着群居的生活。