【正文】
pleasant, collect, protect, some, take care of, try one’s best, as soon as, cut down, pick up, visit One day I one of my friends in a big town. Suddenly, a piece of beautiful music came to my ears. My friend’s father quickly some bags of litter and went outside. I asked my friend, “What’s going on?” My friend said that there was a truck litter outside. “Whenever someone throws some litter in, it gives out beautiful music. other people hear it, they’ll go out with their litter and throw it in.” “It’s a way to help keep our city clean,” said my friend. our environment is very im