The sheep was quietly eating grass.

He is raising a sheep.

The membrane of this cell is very thin.

He received the letter challenging him to a duel and began preparing for the duel.

His role is to fulfill his responsibilities as a leader.

Gender roles are an important element in defining individual behavior in society.

It is important to understand the importance of health.

The consent of the guardian is necessary.

Protectionist policies are introduced to protect domestic industries from foreign competition.

He committed another crime while on probation.