My dream is to travel the world.

The success of this project is a combination of many components.

Health is very important.

His opinion is very important.

Oil is an important element of the world economy.

He is an expert in economics.

We have a responsibility to make this world a better place.

It is important to understand the importance of health.

He is an expert in petrochemistry.

On a cold winter night, a kerosene heater is indispensable.