The signal turned red, so I stopped.

The atomic number of helium is 2.

Could you tell me your number?

We prepared for tomorrow's meeting.

She loves the sound of the music box.

Diamond is the hardest mineral on Earth.

Strong interaction is one of the four fundamental forces in particle physics.

Gravitational interaction creates attraction between objects.

Electromagnetic interaction is one of the fundamental forces used to explain the force between substances.

Weak interaction is one of the four fundamental forces between elementary particles.