结合实际，说说如何抓住关键建设班集体。

     On December 7-18, 2009, there was a meeting about climate change in Copenhagen (哥本哈根),
Denmark (丹麦).    1    A warmer earth does a lot of harm to our lives and the environment. Spring is
arriving earlier. There are more and more droughts (干旱). Because of these, many kinds of animals
and plants may disappear.    2    Many plants will stop growing. Lots of people and animals will not
have enough food.
      People are cutting more and more trees.    3    If we want to have a better future, what should we
do then? Walk to school.    4    If your school is far away from your house, take a bus. Use air
conditioning (空调) as little as you can. You can wear more clothes in winter and use a fan in summer.
    5    Use energy-saving lights.