The two main kinds are discrete and continuous.
there are far more than two main kinds of submarines. The only two sections I can think of to separate them are fast attack and Boomers or Ballistic Missle.
kinetic and potential
consumers and producers.
indentured and chattel .|.
quiet and explosive
Sail boats and power boats are the two main types of pleasure craft.
The two main types of swamp are "true" or swamp forests and "transitional" or shrub swamps.
# LIES # CHEATING Lack of effective commuication.
The action verb and the linking verb.
Eucalyptus and Australian acacia
There are more than two types of kickboxing. The main ones are American and Thai, but in Thai there are several different kinds.