One possible version:

     The students in our class took part in an activity of"Experience a Low-carbon Day" during the Labor Day

vacation. As we know, at the last Copenhagen conference in Denmark, politicians and activists are fighting for

making bigger cuts in carbon emission. We are all looking for a big shift to have a greener world.

      In the morning, we went to the park by bus instead of going by car, which means choosing a low-carbon

transportation.At noon, when we dined out in a restaurant, we refused to use the disposable chopsticks served

there. Instead, we each took with us a lunch box in which there was a pair of chopsticks and a spoon. Besides,

to avoid the damage the free plastic bags caused to the environment, when we went shopping at a supermarket

in the afternoon, we didn't use plastic bags but carried environmentally friendly ones.We didn't come home until very late in the evening. Being extremely hot at night, our neighbours had to turn on the air conditioners but we

used electrical fans to cool ourselves down.

     I think what we did on that day was meaningful, which helped us to form a good habit. We should also call

on the people around us to do something for low - carbon life. Only in this way will the earth be a good place to

live on. Thus, it's time for us to develop low-carbon habits in our daily life.