I don't know how to solve this situation.

His house is very big.

The profits of this company increase and decrease every year.

Population fluctuations greatly affect the economic situation.

His opinion had a big influence on my decision.

That news greatly influenced his opinion.

The population of Japan is decreasing.

He is an expert in economics.

He is a 'big friend', an adult fan of that anime.

His words had a great influence.