1. The sun having set, we started for home.
2. After the sun had set, we started for home.
3. Because the sun had set, we started for home.
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Does #1 mean #2 or #3?
4. The sun set, so we started for home.
5. The sun had set, so we started for home.
(Which one is correct? Are both correct?)
Yes, 1, 2, and 3 all mean the same thing.
Both 4 and 5 are correct, although in 5, we were probably driving in the dark. In 4, we may not have had to drive in the complete dark yet!