The two main kinds are discrete and continuous.
consumers and producers.
kinetic and potential
indentured and chattel .|.
The early SS and the newer GATO Class diesel submarines.
There are now 'Attack' submarines who's main purpose is to sink enemy submarines and ships and also Missile submarines whose main purpose is to launch ballistic missiles at the enemy.
quiet and explosive
1. Ballistic submarines 2. Attack submarines
The two main types of swamp are "true" or swamp forests and "transitional" or shrub swamps.
Sail boats and power boats are the two main types of pleasure craft.
The action verb and the linking verb.
Eucalyptus and Australian acacia