The 20th century was marked by significant advancements in science and technology.

He unveiled his new invention.

He invented a new machine.

Health is very important.

His opinion is very important.

This is an important invention of the 20th century.

It is important to understand the importance of health.

The atmosphere of the end of the century is drifting in this town.

We don't need to reinvent the wheel.

By regularly checking the key performance indicators, you can understand the performance of the company and devise improvement measures.