His grandfather fought in the Second World War.

World War II lasted from 1939 to 1945.

He fought bravely in that great war.

It is important to learn the history of the World War.

Calculating the natural logarithm is an important part of mathematics.

The crown prince is a symbol of the people's hope and respect.

Somatic cells are part of the cells that make up an organism's body.

Pop culture can be said to be a mirror of society.

In Japan under the Ritsuryō system, the Grand General ruled the country.

I am using a calculator to calculate the common logarithm.