His actions are always proper.

This number is ten times ten-duodecillion.

Masashi is my best friend.

Naomasa is my best friend.

I think his answer is correct.

Orthoclase is a type of mineral, mainly found in granite.

There are more than a billion quintillion stars in this galaxy.

A regular polyhedron is a polyhedron where all faces are the same shape.

The cathode of this battery is made of copper.

These two variables are in a proportional relationship.