Please teach me how to find the greatest common divisor.

She described the pain of a broken heart as tears.

I don't know a thing about him.

He emphasized his belief by saying, 'I believe in order to understand.'

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

She is conducting research on the world's oldest profession.

Old World monkeys primarily inhabit Africa and Asia.

The World Trade Organization is an important organization that sets the rules for international trade.

The World Health Organization is working to improve public health worldwide.

New World monkeys live in South America.