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.

The smell of this flower is very good.

The air in this area is greatly affected by pollutants emitted from factories.

The existence of dark matter has not yet been fully proven.

Antibiotics don't work for colds, so please don't take them unnecessarily.

It is said that antimatter has properties opposite to those of matter.