Akiko is my best friend.

Arisa is my best friend.

He is suffering from a subacute illness.

This species has different characteristics depending on its subgroup.

This airplane flies at subsonic speed.

I learned about the reaction of nitrous acid in chemistry class.

Hypochlorous acid is a hypo compound of chlorine.

The British Indian Ocean Territory is a region managed by the UK.

The British Antarctic Territory occupies a part of the Antarctic continent.

My grandmother drinks Panax ginseng tea every day.