The day before yesterday,my classmates and me(要用 I) went to the park near my (our) school.Can you guess(去掉 that) what we did there?Not for amusement but (to take 改为 took) part in a volunteer labour.They(应该是 We) reached the park at nine o'clock.The whole class divided into three groups.Group One planted trees and watered flowers.Group Two was told to pick up litter leaving (过去式要用 left)by the tourists and cleaned all the benches.The group (where 改为 which) I was in wiped all the equipments in the Children's Playground.All of us worked (hardly 改为 very hard).Before noon we finished working.Each of us fell (是 felt)a little bit tired,(so应该是 but) we were happy because we had done a good deed.
已替你更正了错漏漏,