Nitrous oxide is one cause of air pollution.

Many large corporations are saving taxes by using tax havens.

Liquid nitrogen is very cold, so care must be taken when handling it.

This dried boiled rice lasts very long, so it's ideal as a stockpile food for disasters.

Krypton is a type of noble gas.

She has a collection of crystals.

He was working as a jailer.

He is learning Sanskrit.

I found a squirrel in the park.

He is an expert in pharmacology.