Could you tell what is the difference between be the first to do something and be the first to have done something? For example:
The country is the first to use nuclear power.
The country is the first to have used nuclear power.
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In context, both probably mean the same thing.
There are many tenses in English. Sometimes there are important differences between them, and sometimes not.
Life if I said, "Bob is in Chicago", that's present tense. He is in Chicago right now (at the time I say it). If I said, "Bob was in Chicago", that's past tense. He was in Chicago at some time in the past. Normally the context would tell you just when. He might still be in Chicago now, he might have left and returned, or he might be somewhere else. Just based on that sentence, you don't know.
But in other cases it doesn't matter. If I say, "Neil Armstrong was the first man to walk on the Moon", or "Neil Armstrong is the first man to walk on the Moon", both sentences mean the same thing. If he was the first, then he still is the first. Nothing that happens later can make him cease to be the first.
Sometimes it's iffy. Like, "Sally was my youngest sister" versus "Sally is my youngest sister". If she was the youngest at some time in the past, she probably still is the youngest. But not necessarily. Maybe my parents have had another child so Sally isn't the youngest any more.
I'm reminded of a time a politician came to speak at my high school, and the principal introduced him as "a former graduate of Northport High School". When the politician got up to speak, he said, "I thought I still was a graduate." Whether he WAS a graduate or IS a graduate should be the same thing.