Regular and irregular lexical verbs

Regular and irregular lexical verbs

Verbs are divided into lexical verbs and auxiliary verbs. Lexical verbs form an open class which includes most verbs. For example, "dive," "soar," "swoon," "revive," "breathe," "choke," "lament," "celebrate," "consider," "ignore" are all lexical verbs.
A lexical verb is said to be regular if its base form does not change when inflections are added to create new forms. An example is:

• Base form: climb
  
• Present form: climb
  
• -s form: climbs
  
• Present participle: climbing
  
• Past form: climbed
  
• Past/passive participle: climbed.

Irregular verbs are ones in which the base form changes; the endings corresponding to each form are not always unique. Examples are

• Base form: catch
  
• Present form: catch
  
• -s form: catches
  
• Present participle: catching
  
• Past form: caught
  
• Past/passive participle: caught

and

• Base form: choose
  
• Present form: choose
  
• -s form: chooses
  
• Present participle: choosing
  
• Past form: chose
  
• Past/passive participle: chosen.

The verb "be" is the only verb in English which has distinct inflectional forms for each of the categories of grammatical forms, with even the present form differing from the base form:

• Base form: be
  
• Present form: am, are
  
• -s form: is
  
• Present participle: being
  
• Past form: was, were
  
• Past/passive participle: been.