In this factory, they are melting iron using an electric arc furnace.

He is learning the technique of arc welding.

He conducted an experiment using an arc lamp.

He is quite a good cook.

I think his Japanese has improved quite a bit, hasn't it?

I am busy with work during the daytime.

My keys are inside the house.

He is an expert in embryology, studying the developmental processes of many kinds of organisms.

The process of embryogenesis is very complex, with continuous cell division and differentiation.

There is a custom of eating rice cakes facing the favorable direction at the New Year.