VOA慢速英语:南非煤炭地区有世界最糟糕的空气

dump - v. to leave or get rid of (something or someone) quickly or without concern

crack - n. a thin line in the surface of something that is broken but not separated into pieces

hot spot - n. a place where there is much danger or fighting

literally - adv. used to stress that a statement or description is true and accurate even though it may be surprising

solar panel - n. a large, flat piece of equipment that uses the sun's light or heat to create electricity