Question

Had he ________ the importance of the meeting, he would have made sure to attend.

• A. known
• B. knew
• C. knows
• D. knowing
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Hint:

In conditional sentences starting with "Had," always use the past participle form of the verb.

Answer 1

The Correct Option is A

Step 1: Sentence structure 
The sentence uses a conditional phrase starting with "Had he," which is a subjunctive form. 
Step 2: Correct verb form 
After "Had he," the past participle "known" is required to form the past perfect subjunctive. 
Step 3: Verify other options 
- "knew" is simple past, incorrect here. 
- "knows" is present tense, incorrect. 
- "knowing" is gerund/participle, incorrect. 
Conclusion: 
The correct form is "Had he known."