Fill in the blank using appropriate tense forms from the options given:
If I had known his address, I _______ to see him.
a) will have gone
b) should have gone
c) would have gone
d) May have going

Hint: From the given question it can be understood that the person actually does not know his address. The usage of had known tells us that she wishes to know his address. Had known is past perfect. The tense to be used in the blank is going to be past perfect.

Complete answer:
Option a is wrong because it means there is a surety that she would have gone to meet him. Will have is a future tense but this will not be used here because she doesn't know his address, therefore there is no way that she will actually go and see him. We use will have when we are looking back at an event from a future point of time but since that is not the case here, we cannot use this option.
Option b is wrong because should have gone implies that it is a compulsion for her to go and meet him. The word should implies force.
Option c is the correct answer because it shows that if she had known his address, she would have gone to see him; but because she does not know his address, she cannot go and meet him. There is no compulsion. “Would have” is the past tense of “will have”. Because the sentence begins with a past tense that is “had known”, the answer in the second blank is also going to be in the past tense. There is to be consistency in the usage of tenses in a sentence.
Option d is wrong because “may have going” is in no way making the sentence grammatically correct.

Note:
It is very important to note that when we have to use two tenses in a sentence, both the tenses should be the same. If the sentence begins with the past tense then it is followed by a past tense. If the sentence begins with a present tense then it is followed by a present tense. If the sentence begins with the future tense it is followed by a future tense. There may be variations like present perfect or future perfect but the first part of the tense that is past, present or future remains the same.