I am doing volunteer work to contribute to the community.

He was watching the situation as a detached observer.

His contribution led our project to success.

He became my guardian.

She is entrusted with the guardianship of the elderly.

She ended up having to watch over her sick grandmother.

My younger brother is diligently practicing Taekwondo every day.

I practice Tai Chi in the park every morning.

I will never forget that experience.

The troposphere is a part of the Earth's atmosphere, extending from the surface to about 10 kilometers.