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.

We visited the moated burial mound and learned about the lives of ancient people.

This game is really fun from the second playthrough.

The Paleolithic is the first era of human history.

The Bronze Age was an important period in human history.

The Neolithic was an important period in human history.

The Mesolithic is the era between the Paleolithic and the Neolithic.

The Azuchi-Momoyama period, also known as the Oda-Nobunaga period, was a very important time in Japanese history.

The Azuchi-Momoyama period was a very important time in Japanese history.