The human immunodeficiency virus is the virus that causes AIDS.

We are here to solve that problem.

They have a variety of opinions, making it difficult to agree.

I read the Letter to the Ephesians and gained a deep understanding of Christian teachings.

He is studying the history of African Americans.

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

She said 'to each his own', respecting the differences among people.

He underwent surgery on the depressor septi nasi.

He was anxious about starting a new business, but I encouraged him by saying, 'Even a journey of a thousand miles begins with a single step.'

World War I was a large-scale war that lasted from 1914 to 1918.