夏天很热 ,自古皆然。但热过了头 ,就成了热灾。河流径流量减少 ,通航受阻 ,水力发电量减少 ;森林、草原、草甸区域频发大火 ;大区域热旱 ,影响农作物生长 ,粮食产量大幅度下降。酷暑影响人们的夜间睡眠 ,使人整日昏昏沉沉 ,交通事故增加 ,工作效率下降 ,对生产、生活影响很大 Summer is very hot, since ancient times. But overheated, it became a hot disaster. River runoff reduced, navigation blocked, reduced hydroelectric power generation; forests, grasslands, meadows frequent heavy fires; drought in large areas, affecting crop growth, grain output dropped significantly. Summer heat affect people’s sleep at night, make people drowsy all day, traffic accidents increase, work efficiency decline, a great impact on production and life