【正文】
and the big population is threatening the nature every second。 to the nature, overpopulation is a big problem。 people, people, people, people。 people pushing their hands through the taxi windows, begging。 people visiting each other, arguing and screaming。 people talking。 people eating。 the streets are crowded with people。 when we enter a crowded slum district。 lets take overpopulation as an example。 what is threatening the nature? air and water pollution, overharvesting of plant and animal species, overpopulation and so on。 and this lasted so long a time。 because of the supplies of the nature, we have lived happily for a long time。 it i