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.

I am very interested in natural science.

He was playing the guitar at the street corner.

Natural numbers start from 0 and continue as 1, 2, 3, 4, 5, 6, 7, 8, 9.

Natural selection plays an important role in the evolution of organisms.