He is my close friend.

He is good at solving addition problems.

He is good at adding numbers.

I'm taking care of my health by having an extra meal every day.

My grandfather used to raise domestic silkworms and make silk.

Peroxidation is one of the chemical reactions, especially involved in the oxidation of lipids.

This apple is a countable noun.

The pig is playing in the mud.

Nobutaka is my best friend.

I'm thinking of having pork buns for lunch today.