It is important to learn about the prevention and treatment of the human immunodeficiency virus.

My younger brother is attending a middle education school.

He came down the stairs.

He is feeling solitude.

The human immunodeficiency virus destroys the immune system, making the body unable to fight disease.

The human immunodeficiency virus destroys the immune system, causing the body to lose its ability to fight disease.

Zoonosis is a disease that spreads from animals to humans, or vice versa.

In order to solve problems, it is important to listen to the opinions of many people, as the saying goes, 'two heads are better than one'.

Ogura Hyakunin Isshu is one of the classical literatures of Japan.

He said, 'If you want to shoot a man, first shoot his horse,' and began to solve the smaller problems first.