The Quaternary is the most recent era in Earth's history.

His first adjective is 'beautiful'.

He is learning how to use the second adjective.

In our company, we always adhere to the principle of safety first.

If the balance of the triple burner is disrupted, you may feel unwell.

He made a model of a triangular pyramid.

Isami is my best friend.

The three states of matter are solid, liquid, and gas.

My younger brother is currently in his third year of high school, preparing for university entrance exams.

Mitsuo is my best friend.