He is troubled by his obsession.

This building needs reinforcement.

Relaxed education is important for nurturing children's creativity.

My father serves as the president of the mutual aid society.

Bats use echolocation to fly around in the dark.

This is my first time crossing the border.

He is working at a school as a student teacher.

It's difficult to understand his situation.

He was an accomplice in the crime.

He has anthropophobia and avoids contact with people.