橘子

In a sentence

• 我喜欢吃甜甜的橘子。

  I like eating sweet oranges.

  Here, 橘子 is used as a noun referring to the fruit 'orange'.

• 这个橘子的颜色非常鲜艳。

  The color of this orange is very vivid.

  In this sentence, 橘子 is again a noun, specifically referring to a particular orange.

• 农场里的橘子树结满了果实。

  The orange trees in the farm are laden with fruit.

  Here, 橘子 is a part of the compound noun 橘子树 ('orange tree'), describing the type of tree in focus.