Original:
Marmots live in burrows. They warn each other about danger with loud whistles. It’s not easy to catch them
Corrected:
Marmots live in burrows. They warn each other of danger with loud whistles. It's not easy to catch them.
Why these changes?
- Periods and punctuation: The last sentence needed a period at the end. Every sentence should end with a period, question mark, or exclamation mark.
- Capital letters: The first word of each sentence already had a capital letter, which is correct.
- Word choice: "Warn each other of danger" sounds a little more natural than "warn each other about danger," but both are okay. You can use either.
- Contraction: "It's" means "It is." The contraction is fine for this sentence.
- Pronoun meaning: "Them" points back to "marmots," so the meaning is clear.
Short tip: Read your sentence out loud. If it sounds finished, put a period at the end.
Nice work! These sentences were already mostly correct — just add the missing period and you are done.