My personal thought is that everyone should be treated equally.

He values his private life.

He was born as an illegitimate child and experienced many difficulties.

My grandfather used to till his privately-owned rice field.

He holds a personal grudge against me.

Using the private railway makes commuting very convenient.

The problem of space debris could potentially have a significant impact on future space development.

The study of cosmic rays may hold the key to unraveling the mysteries of the universe.

He proposed a new theory about cosmology.

He believes that aliens exist.