雨,是常见的降水现象,若是长期干旱,农田龟裂,饮水困难,这时突降透雨,人们称为“久旱逢甘霖”。如夏季连日高温,忽来阵雨,顿时空气清新,给人们带来几许凉意,颇感适意。所以说,适时的雨是喜雨,唐代大诗人杜甫,有诗赞道:“好雨知时节,当春乃发生,随风潜入夜,润物细无声。”久雨不止称淫雨,过量的雨水会带来灾难,且不说外地山洪暴发,江河泛滥,洪涝成灾。单说特大城市上海,地势低平,建筑密布,空地绿地很少,雨后往往内涝,造成马路积水,工厂仓库受淹,居民住宅进水。雨涝之 Rain is a common precipitation phenomenon. If it is a long-term drought, the farmland is cracked and drinking water is difficult. At this time, sudden rain falls, and people call it “a long drought and frequent rain.” Such as the high temperatures in the summer, suddenly came showers, fresh air suddenly, giving people a lot of cool, very comfortable. Therefore, the timely rain is hi rain. The great poet Du Fu in the Tang Dynasty praised the poem: “When rain is known, when spring occurs, the wind sneak into the night, and the moistens are silent.” “Long rain is more than just kinky rain. The rain will bring about disasters, not to mention the outbreak of flash floods in other places, flooding of rivers and floods. The single-speaking city of Shanghai is said to be a low-lying city with a densely populated building. There are few green spaces in the open air. After the rain, there are often guilty floods that cause roads, flooding of factory warehouses, and flooding of residential buildings. Rainy