Adverb clauses of condition are introduced by the subordinating conjunctions if, whether, provided that, so long as and unless.
- If I like it, I will buy it.
- If you heat ice, it melts.
- If it rains, we will stay at home.
- You may come, if you want to.
- You won’t pass unless you work hard.
- You will be shot unless you give me the keys of the locker.
- There will be no problem provided that you keep your mouth shut.
- You will have to take the medicine whether you like it or not.
You may have noticed that the adverb clause of condition gives the circumstances under which the action in the main clause will take place.
Omission of if
Sometimes the conjunction if is omitted.
- Were the child mine, I would have taken it to a doctor. (= If the child were mine, I would have taken it to a doctor.)
- Should you meet my brother, tell him that I have gone to the railway station. (= If you meet my brother, tell him that I have gone to the railway station.)
Clauses of condition are sometimes introduced by a relative pronoun, or adjective or adverb.
- Whatever happens keep calm.
- However cleverly you may cheat, you will ultimately get caught.