Mr. Mashita is my friend.

Mr. Shimooki is my best friend.

Various cultures exist under the sky, meaning in the whole world.

His lower jaw was strong, as if showing determination.

She used her depressor labii inferioris to lower the corners of her mouth.

If you don't get regular dental check-ups, you may develop periodontitis.

If you don't have regular dental check-ups, you may develop periodontitis.

The saber-toothed tiger is a type of extinct mammal.

Rodents are widely distributed around the world.

In phonetics, a sibilant is used to represent a specific sound.