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.

The law of ideal gas is a basic concept in physics.

He is an expert in toxicology.

Lithium aluminium hydride is necessary for this chemical reaction.

Please use the emergency stairs in case of a fire.

Due to the earthquake, the city declared a state of emergency.

Hydrocarbons are fundamental components of organic chemistry.