墨西哥

In a sentence

• 我的朋友来自墨西哥。

  My friend is from Mexico.

  In this sentence, '墨西哥' is used as a proper noun representing the country Mexico.

• 墨西哥的饮食非常独特。

  Mexican cuisine is very distinctive.

  Here '墨西哥' functions as an adjective modifying the noun '饮食' (cuisine), indicating the origin of the cuisine as Mexican.

• 我学到了关于墨西哥的许多事情。

  I learned many things about Mexico.

  '墨西哥' refers to the country as a subject of learning or discussion in this context.