He is really a shameless person.

He contracted brucellosis after returning from a trip abroad.

Restoring this old house is a tough job.

Every weekend, I do volunteer work at a local shelter.

He is known as an activist for environmental issues.

He is a very active person.

Action potential is an important mechanism for nerve cells to transmit information.

He is passionately engaged in extracurricular activities.

He is suspected of being involved in the sabotage of the company.

He is suspected of being involved in the sabotage of the company.