It ______ useless to persuade a stubborn man.
It ______ useless to persuade a stubborn man.
Explanation
The subject "It" is singular and refers to a general truth or fact.
For general truths, we use the present tense, so "is" is correct.
The subject "It" is singular and refers to a general truth or fact.
For general truths, we use the present tense, so "is" is correct.