Keigoku is my best friend.

His surroundings were quiet, and there was no one around.

We celebrated our 10th wedding anniversary.

How long is the perimeter of this rectangle?

Zhouli is an important document that describes the ancient Chinese rituals in detail.

I live in Shunan city.

A round angle is 360 degrees.

Please remember this old proverb, 'A noble man compares and does not compete, a petty man competes and does not compare.'

This diode only allows current to flow in one direction.

This old radio uses a pentode.