He is a person with a strong heart.

He finished the job in slightly more than an hour.

Tsuyoshi is my best friend.

He is a very strong person.

His strength comes from his mental power.

He is an expert in chemistry.

I learned about the reaction of nitrous acid in chemistry class.

Acid rain destroys forests and has a serious impact on ecosystems.

He always supports my opinion.

I carry my lunch box every day.