His father is a very strict person.

The teaching of this unit is very important.

He was sentenced to a severe penalty for that crime.

I will decide to purchase after checking these goods.

We require strict adherence in this project.

I was surprised by his stern attitude.

It is important to identify the source of infection.

The Proterozoic eon is the longest era in the history of the Earth.

The Eoarchean eon is the oldest era in the history of the Earth.

He was traveling alone in the wilderness.