We are searching for extraterrestrial life.

I am an Earthling.

Earth science is an important field of study for unraveling the mysteries of nature.

The process of terraforming is part of transforming other planets into a habitable environment for humans.

Her graceful movements are just like a ballerina's.

This treaty was concluded to strengthen the friendly relations between the two countries.

He is training to strengthen the tightening of his muscles.

He tightened his fists in tension.

I made a reservation at the restaurant.

This sentence is written in a contracted form.