1. It has taken many centuries of wars and fightings for mankind to learn this.
2. It took many centuries of wars and fightings for mankind to learn this.
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Why do we have to use 'has taken' as in Sentence 1? What about Sentence 2, where the past tense 'took' is used? What is the difference between #1 and #2?
1. "has taken" means it happened in the past and is still happening now. (Also, you need to change "fightings" to "fighting" -- there is no plural form for that word.)
2. "took" means it happened in the past and does not continue into the present.