《大自然警号长鸣》是一篇议论文。文章开头叙述作者听新闻广播，由此引出关于东北虎数量锐减的具体说明，再由虎说到多种野生动物受害的情况，又由野生动物说到自然生态环境的危机———如此层层推进，为下面的议论作了铺垫。接着分条陈述我国在自然生态环境方面的不利条件， “Nature sirens chanting” is an argumentative essay. At the beginning of the article, the author stated that the author listened to news broadcasts, which led to a detailed description of the sharp decline in the number of tigers in the country. Tiger then said that a variety of wild animals were victimized, and that wildlife was a crisis in the natural ecological environment. Layer advance, laying the groundwork for the following discussion. Subsequent sub-statement of China’s disadvantageous conditions in the natural ecological environment,