He was making a model of a tetrahedron.

My new four-wheel drive runs stably even on snowy roads.

He continues to practice in search of complete enlightenment.

He warned the young people, saying 'At thirty, one should not be careless, at forty, one should not be indecisive.'

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.