【正文】
manently impaired our mother earth. as we tragically learned from last summers floods. we cannot continue our carelessness. finally, standing here at the threshold of the 21st century, we cannot help thinking of our posterity. nature is not only the mother of the present generation, but also the mother of the generations to e. how severely our descendents will criticize us if we leave them a barren and lifeless mother? how much more they