His business ended in failure.

Einstein's theory of relativity is one of the important theories in physics.

Einstein's theory of relativity forms the basis of physics.

Today's relative humidity is 70%.

He has an excellent relative pitch, and can play any song immediately.

His success is small, relatively speaking.

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.

Believing that failure is a stepping stone to success, he challenged again.

Believing that failure leads to success, he continued to challenge himself over and over again.

The special theory of relativity is a theory proposed by Einstein.