众所周知，在我们所生存的世界里有着千千万万的细菌，它们飘浮在人们所呼吸的空气里，隐藏在人们所摄取的水和食物中，甚至存在于我们人体的许多部位，如皮肤表面，呼吸道，口腔和胃肠道等。细菌可以引起疾病，给人们带来痛苦、灾难，甚至是死亡。许多年来，人们一直以为当细 As we all know, there are thousands of bacteria in the world we live in. They float in the air that people breathe, they are hidden in the water and food that people ingest, and they even exist in many parts of our body, such as the surface of the skin. , respiratory tract, mouth and gastrointestinal tract etc. Bacteria can cause illnesses and cause people suffering, disasters and even death. For many years, people have always thought that when