The Hadean eon is considered the first era of Earth, lasting from about 4.6 billion years ago to 4 billion years ago.

The Precambrian eon occupies most of Earth's history.

E. coli is one of the bacteria that normally reside in the human intestine.

He is passionate about studying modern language.

He, a music college student, is very good at playing the piano.

He vowed to live through this world and the next with the spirit of once-in-a-lifetime encounter.

We check the quality of the products on this inspection table.

My younger sister is attending a junior college.

I like watching street performances in the park.

A new approach is needed to solve this set of problems.