Difficulty: Easy
Correct Answer: had tried
Explanation:
Given sentence
If he would have tried he would have succeeded.
Concept/Approach
In standard English, the if-clause of a third conditional uses the past perfect, not 'would have': If + had + past participle → would have + past participle.
Correction
If he had tried, he would have succeeded.
Why others are wrong
'is tried'/'was tried' → change meaning (passive) and tense; 'No improvement' leaves a common learner error.
Final Answer
had tried
Discussion & Comments