Question

Select a suitable adverb clause (conditional) to complete the sentence:
We will be able to buy this house ______.

• A. after coming back
• B. only if we earn enough money
• C. once it gets repaired
• D. none of the above

Answer 1

The correct option is B only if we earn enough money

An adverb clause is a group of words containing a subject and a verb, and it functions as an adverb, by modifying an adjective, verb or an adverb. Adverb clauses generally begin with a subordinate conjunction (since, because, while, etc.).
Option B is correct because it is an adverb clause of condition, 'only if' is a subordinate conjunction that refers to a condition that is necessary.
Option A is incorrect because it is a phrase, not a clause.
Option C is incorrect because it is an adverb clause of time, not condition.
Option D is incorrect because the answer lies in B.