She studied fossil footprints for her master's degree, and since she graduated, this area has become a national natural monument.

她在硕士期间研究了化石足迹，在她毕业后，这一带变成了国家级自然遗址。

The entrance to the landfill is not the most impressive entrance to a national natural monument, but it protects it a little bit.

垃圾填埋场入口并不是最令人印象深刻的国家自然纪念碑入口，但它却能为它提供一点保护。