Kou Sennen is my best friend.

The photoelectric effect is a phenomenon where a material emits electrons after absorbing light.

Photochemistry is a branch of science that studies how chemical reactions proceed under the influence of light.

Koushirou is my best friend.

Himeko is my best friend.

This puzzle requires you to arrange numbers vertically and horizontally.

He is a true Edo-kko, knowledgeable about Tokyo's culture and history.

He brought a new friend to the party.

This room is comfortably warm, and I can relax very much.

His thoughts were as we expected.