This beautiful apophyllite is part of my treasure collection.

He searched the forest to find a red junglefowl.

The cumulonimbus clouds floating in the sky indicate that a thunderstorm is near.

He is an expert in gemology, and he is good at evaluating the quality of diamonds.

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

We conducted a meta-analysis on this issue.

I often read e-books.

Complex analysis is a branch of mathematics that studies functions of complex numbers.

He is an expert in harmonic analysis.

This contract includes a warranty against defects.