These clauses are usually introduced by the conjunctions if, whether, provided that and so long as.

• If you heat ice, it melts.
• If it rains, we will not go out.
• You won’t pass unless you work hard.
• There will be no trouble provided that you keep your mouth shut.
• I will forgive you on condition that you don’t repeat the offence.

You will notice that the adverb clause of condition gives the circumstances under which the action in the main clause will take place.

Sometimes the conjunction if is omitted.
Compare:

• Were I you, I wouldn’t do it. (= If I were you, I would not do it.)

Related posts:

1. Kinds of adverb clauses
2. Adverb clauses of cause
3. Adverb clause of purpose
4. Adverb clauses
5. Adverb clauses of time
6. Adverb clauses of place
7. Noun clause
8. Clauses
9. More about adjective clauses
10. Adverb clauses of degree or comparison