This is a model of a mutetrahedron.

We are aiming to kill two birds with one stone with this plan.

Verbs of the lower second conjugation are important for understanding Japanese grammar.

In learning Japanese grammar, understanding the upper two-step conjugation is important.

At the school sports festival, we did a three-legged race.

A binary operator is one of the basic concepts in algebra.

The goods in this store are being sold for dirt cheap.

He goes to the gym every day to train his biceps brachii muscle.

She was going through puberty and was confused by the changes in her body.

Nitrous oxide is one cause of air pollution.