This equation has homogeneity.

Solving a linear equation is difficult.

Keijiro is my best friend.

Sennenji is my best friend.

He always sticks his nose into other people's business like a busybody.

He was affected by secondary effects.

In behavioral sciences, the use of metatools plays a crucial role.

She was going through puberty and was confused by the changes in her body.

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

World War II lasted from 1939 to 1945.