1. We did the clean-up activities near the Nakdong River.
2. We picked up garbage at Haeundae Beach.
3. We picked up trash and put it into a plastic bag.
4. We mopped the floors of the building.
5. We sweeped the floor and cleaned it with a mop.
6. We learned how to use ropes when we climb the mountains.
7. We sang chants and solved cross word puzzles.
8. We played some dice games and drew cartoons.
9. We cooked meals with the ingredients we had.
10. We danced around the bonfire together.
(Woould you check the expressions above and correct the errors, please?)
In #5, swept (not sweeped).
In #7, crossword (one word, not two).
Everything else is fine.