He is recognized as the top person in that field.

The human immunodeficiency virus is the virus that causes AIDS.

When he had a problem due to his own actions, he remembered the phrase 'chickens come home to roost'.

At the school sports festival, we did a three-legged race.

He is an expert in fluid mechanics.

My father is an expert in otolaryngology.

He is immersed in the research of deep learning.

He has a learning disability, but it does not diminish his desire to learn.

Chemotransmitters play an important role in the transmission of information between nerve cells.

The mylohyoid muscle plays an important role in opening the mouth.