Mr. Ue is my best friend.

In ancient documents, the word '上' was used to refer to gods.

Mr. Ue is my best friend.

My room is on the second floor, and your room is above mine.

Taxonomy is an important tool for understanding the diversity of life.

This library adopts its own classification method.

An imaginary unit is an important concept in mathematics.

An astronomical unit represents the average distance from the Earth to the Sun.

This product has a very small assembly unit.

An identity matrix is a square matrix in which all the elements on the diagonal are 1 and all other elements are 0.