What on earth is he thinking?

This project is focused on a single goal.

This project is focused on a single goal.

He doesn't waste even a single grain of rice.

He knows nothing about that one case.

One part is important.

I use a set square to draw shapes.

In chemistry class, I learned about acid anhydride.

In chemistry class, I learned about acidic oxides.

Lower fatty acids play an important role in the human body.