construction unit的用法和樣例：
例句
- The basic structural unit of yarn is the fiber.
纖維是紗的基本結構單元。 - Its morphological structure unit is a rodlike macromolecule which drrdnges regularly to form domdins, then these domains pack further to form a rodlike submicroscopic structure.
其形態結構單元是由棒狀分子規整排列形成的微區。
