Let's look at your sentence about the Northern gannets:
Original sentence: "Northern gannets don’t float on the water, but fly over the waves looking for fish. Once, they find a big group of fish, they dive one after another to catch fish."
Here is the corrected version:
"Northern gannets don’t float on the water but fly over the waves looking for fish. Once they find a big group of fish, they dive one after another to catch them."
Explanation of the corrections:
- Removed the comma before "but" because when "but" connects two parts of the same sentence without changing the subject, we usually don’t put a comma.
- Removed the comma after "Once" because "once they find a big group of fish" is one phrase, so no comma is needed there.
- In the second sentence, changed "to catch fish" to "to catch them" so it sounds less repetitive. "Them" refers to the fish.
You did a great job writing the sentence! The small changes help it sound clearer and smoother.