For is used to show purpose, benefit, duration, or direction, as in doing something for someone, for three hours, or leaving for school. It helps link actions with reasons or goals.
“For” comes from Old English “for,” meaning “before, because of, or for the sake of,” from a Proto-Germanic root. It is one of the oldest and most basic function words in English.
Because “for” is so tiny and common, learners often overlook how many jobs it does—purpose, support, exchange, time, and more. Mastering its patterns quietly unlocks a lot of natural-sounding English.
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