Finite and non-finite clauses

For a sentence to be complete in English, it requires a finite verb.  A finite verb shows tense and can also show number and person when using the present tense (e.g. ‘sings’ denotes present tense, third person singular). A finite clause or sentence can stand on its own and make sense, e.g.

She is staring into space. (present progressive/continuous)

He was frightened by the traffic. (simple past - passive voice)

She frightened the cat. (simple past)

In the above examples, as in usual sentences, the subject is included.  When present or past participles are used as a non-finite verb, the subject is rarely included and the participle appears on its own.  E.g.

Staring into space – present participle ‘staring’

Frightened by the noise – regular past participle

Lit by a candle - irregular past participle

Past participles often look like the simple past tense with regular verbs having the same –ed suffix. However for irregular verbs (often the verbs coming from Old English), the form is different.  (For more on past participles, click on the past participle label on the right-hand side of my blog.)

Clauses containing non-finite verbs are called non-finite clauses.  Because they don’t contain a finite verb, they can’t be the main clause in a sentence as they would not make sense standing alone as a simple sentence. Therefore, they must stand as a subordinate clause and require a finite clause to complete the sentence.  In this way, complex sentences are formed.  

Staring into space, he heard nothing around him.

Frightened by the noise, the horse reared up.

Lit by a candle, the room looked romantic.

Using participles in non-finite clauses to create complex sentences adds variety to children’s writing. They can also experiment with swapping the clauses around for effect (and investigating the correct punctuation to use).  What is more effective?

Frightened by the noise, the horse reared up.

The horse reared up, frightened by the noise.

We can also add ‘to’ to the base form of the verb to create another non-finite form: the infinitive, e.g. to light, to drive.

To light a candle, you will need a match.

Non-finite clauses encourage children to vary their sentence structure.  In effect, the non-finite construction is filling the same function as a conjunction, by joining two clauses together within a sentence.