Not long ago the movie 2012 came into screen. The people were threatened by those scenes of destroying flood, severe earthquake, terrifying hurricane and constructions representing human civilization being destroyed and even swallowed by disaster.  Luckily, they are just the director' s imagination, but the present situation is not heading a positive direction, either. Take my own experience in Alaska as an example. Once I took a trip to the glacier. Along the way there stood signposts marking the snow lines of different years.  They started from the foot of the mountain, but it was at the top when I finally saw melting glaciers . My heart ached seeing the beautiful blue ice melting at every second. Sad but true, they are the effects of global warming and the result of our human impact. Furthermore, each year the rising sea level will kill 56 million people, and that's about the population of the entire Italy. According to studies, if the temperature keeps on rising like this, by the year 2050, some islands and coastal cities including New York, Shanghai, Tokyo and Sydney will be drowned in water. Our fortune is in our own hands. It depends on us to shape our future, to reduce future human impact and find ways to form a peaceful relationship with our environment. Therefore, it's time for actions to be taken right now. Contribute a little to energy saving by using more efficient light bulbs and less hot water. Let recycle become our habit by thinking twice before throwing something away. Let us take public transportation as our first choice when going to a certain place. It might cost more time for now, but it' s to the benefit of a permanent future. Take care of every tree and grass around us by watering them or simply just avoid destroying them. In a word, _ The earth does not belong to us. On the contrary, we belong to the earth. Please bear in mind that the earth is our home. It is our responsibility to build a brighter and better future of our planet and prevent what happened in the movie 2012 from becoming reality. According to the passage, you are advised to   _  .
drive our own private cars instead of taking buses to some place recycle everything that is used go to see the movie 2012 at once work together to take good care of our planet