It's difficult to remember words with irregular conjugation.

I requested a refund because the product was defective.

The product was defective, so I asked the clerk to return the money.

His amygdala is working very actively.

This area is rich in schist.

He was in charge of the editorship of that science book.

This cake has a strong flavor of bitter almond.

This exam is taking an irregular format.

He was demoted and exiled from the company because his misconduct was discovered.

He was demoted and exiled because his misconduct was discovered.