In the following question, out of the four alternatives, select the alternative which will improve the bracketed part of the sentence. In case no improvement is needed, select "no improvement". Father (would have been appreciated) your efforts if you had informed him.?

Option 2 : would have appreciated

The correct answer is would have appreciated

• The subordinate clause of the sentence is in the past perfect tense (subject + had + third form verb). To maintain the uniformity of the sentence the main clause will have the structure as "would have + past participle". Hence, the main clause will take the verb phrase as:- "would have appreciated".
• The given sentence is a third conditional sentence.
• A third conditional sentence is used to imagine a different past that did not happen.
• Some Examples:-

1. If I had been present, I should have enjoyed it a lot. 
2. If I had been present, I would have enjoyed it a lot. 

The correct sentence is- Father would have appreciated your efforts if you had informed him.