In poor countries, where climates are often hotter and more humid, public-health systems are weaker and preoccupied with other threats. Often, adaptation to extreme heat is done by charities if it is done at all. Particular attention should be paid to reaching both remote areas and densely populated urban ones, including slums where small dwellings with tin roofs packed together worsen the danger that uncomfortably high temperatures will become lethal. 贫困国家的气候往往更炎热潮湿，公共卫生系统更薄弱，且疲于应付其他威胁。如果真有人在应对酷热的威胁，通常是慈善机构。防暑行动应特别注意覆盖偏远地区和人口密集的城市地区，包括贫民窟，那里狭小的铁皮房密集，令难耐的高温更加致命。
——《经济学人》
外刊音频 来自我爱背单词 00:00 00:30 基本释义
A substance that is lethal can kill people or animals.在希腊神话中，冥府（Hades）有一条河叫Lethe，汉语通常译作“忘川”或“忘河”，死者的阴魂喝一口忘川之水就会忘却人间和世事。
拉丁语letum表示“死”，所以英语单词lethal就表示“致命的，致死的”。
英语里还有两个非常重要的同根词：
lethargic adj. 无精打采的，懒洋洋的
fatal: A fatal accident or illness causes someone's death.（致命的）
deadly: If something is deadly, it is likely or able to cause someone's death, or has already caused someone's death.（致命的）
