This amplifier improves the sound quality.

The compound eyes of insects are made up of many small lenses.

He expressed dissatisfaction with the result.

He voiced his dissatisfaction with the result.

I went to the doctor because of sinusitis.

My sinuses are blocked, and I have a headache.

My sinuses are blocked and I have a headache.

I wore a hanbok and experienced Korean culture.

He finds it difficult to understand complex sentences.

His secondary role greatly contributed to the success of the team.