An example of the subordinate clause working like an adverb: The match will be cancelled if it rains. The clause ‘if it rains’ adds detail and gives a reason to the verb 'cancelled'.

Adverbial clauses are subordinate clauses that function as adverbs in sentences. Normally, adverbial clauses describe adjectives and verbs and must contain a subject and a verb.

All three clause types function as adverbial clauses. I propose that the distribution of these clause types is due to the degree of certainty of the truth of the subordinate clause proposition, ...

An essential relative clause provides necessary, defining information about the noun. On the other hand, non‐ essential relative clauses provide additional, non‐necessary information about the noun.