He is the direct line of the family.

Patriarchal society causes a lot of gender injustice.

Matriarchal society is becoming more common in many places around the world.

The corollary of this theorem is very important.

This matter does not concern our plan.

The Viet-Muong language family is a major language family in East Asia.

The factions in this game are very diverse.

Rock formation

Our frame of reference is the perspective of the Vietnamese people.

Coordinate system is a way to determine the position of a point in space.