Final answer:
The adverb clause in the sentence is 'unless you invite him', which provides the condition for the main action 'he will not come'. It begins with the subordinating conjunction 'unless' and cannot stand alone without the main clause.
Step-by-step explanation:
The adverb clause in the sentence 'He will not come unless you invite him.' is 'unless you invite him'. An adverb clause is a group of words that functions as an adverb, meaning it provides more information about how, when, where, why, to what extent, or under what condition the action in the main clause takes place. In this case, 'unless you invite him' is providing the condition under which 'he will not come'. This type of clause starts with a subordinating conjunction like 'unless', which indicates the dependency of the clause on the main part of the sentence.
In example sentences involving dependent clauses, we can see that such clauses can't stand alone. They always need an independent clause to complete their meaning. Let's consider this with another example 'If Jad doesn't finish his homework on time, he won't go to the party.' where 'If Jad doesn't finish his homework on time' is the dependent clause, starting with the subordinating conjunction 'if'.