About

Each English verb has from two to eight distinct forms (changed spellings and pronunciation). Four of these are sometimes called the ‘principal parts’: the present, past, past participle and present participle.

The finite forms
Finite forms have a specific time reference (tense) and are in part inflected for person and number. They may serve as the main verb in either independent or dependent (subordinate) clauses.

• present An inflected form with the suffix -s is used for the 3rd person singular. Be has distinct forms (am and is) for both the 1st and the 3rd persons singular.  

  USES:

  • to express states which are currently true and actions which are habitually performed in the present:  I feel very good today.  John runs every day.
  • to express intended future actions or states:  We are meeting at 3 o’clock.
    
    

• past This is formed with the -(e)d suffix in weak verbs, with vowel change in strong verbs, and variously in irregular verbs. Be has a distinct form for the 1st and 3rd persons singular. 

  USES:

  • to express states which were true at a given point in the past and actions completed in the past.  Mary seemed sad.  Ed wrote a book.
  • to express some degree of improbability in the IF clause of conditional constructions. In these cases it is not inflected for person. This use is called the past subjunctive in traditional grammar.  If I were there I would give you a big hug!
    
    

The non-finite forms
Non-finite forms have no specific time reference and are not inflected for number or person. They are used

• as the main verb in some dependent clauses (but not in independent clauses)
• as components of verbal constructions expressing specific tenses and aspects
• as other ‘parts of speech’: nouns, adjectives, adverbs (with the –ly suffix), and even prepositions (during, granted).

Modal verbs (can/could, may/might, shall/should, will/would, must) are defective: they have no non-finite forms which can serve the uses described below. However, the finite forms of some modals are occasionally used as nouns:  This show is a must! Cans and woulds are useless: we want action.

• infinitive For all verbs except be this is identical with the present form.  

  USES:  

  • unmarked (‘bare infinitive’) in constructions with modal verbs to express modality and futurity:  She may come tomorrow.  That could be risky.
  • marked with to (‘marked infinitive’) in constructions with semi-modal verbs (need, ought, &c) and some lexical verbs (have, be, &c) to express modality:  Bob needed to find a replacement.  We ought to investigate that.  You have to go.  
  • marked with to, with or without a subject, as the main verb in subordinate and complementary clauses:  Napoleon ordered Soult to abandon Austerlitz.
  • marked with to, but with no subject or objects or complements, as a noun phrase:  To err is human.
  • unmarked as the main verb in certain subordinate clauses expressing an action commanded or requested; this use is called the present subjunctive in traditional grammar.  We ask that you be here at 7 p.m.
    
    

• past participle This is identical with the past form in weak verbs; formed with vowel change, and sometimes an -(e)n suffix in strong verbs; and formed variously in irregular verbs.  

  USES:

  • in constructions with be to express the passive voice: Brad was promoted to Vice President.  My phone was broken in the accident.
  • in ‘perfect’ constructions with have to mark events as occurring before reference time but still having relevance at the reference point:  They had deceived us many times before.
  • as an adjective to express having suffered an action, if transitive, or having performed an action, if intransitive:  He is a marked man.  She is a widely traveled woman. If the participle takes verbal arguments such as objects, complements or locatives, or is modified by a following preposition phrase, the participle phrase is placed after the noun it modifies: He is a man marked for future promotion.
    

• present participle This is formed with the -ing suffix on the infinitive form.  

  USES:

  • with be to express progressive (continuous) aspect:  We are building a house in Chesterfield.

  • as an adjective to express performance of an action at reference time: The running child tripped and fell. When the participle takes verbal arguments such as objects or complements, or is modified by a following preposition phrase, the participle phrase is placed after the noun it modifies: The child running across the playground tripped and fell.

  • as a ‘gerund’ capable of playing the syntactic role of a noun, but with verbal arguments: Playing golf is my favorite pastime.