Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
certificate – n. a document that is official proof you have finished school or a course of training
literacy – n. knowledge that relates to a specified subject
slum – n. an area of a city where poor people live and the buildings are in bad condition
solar panel – n. a large, flat piece of equipment that uses the sun's light or heat to create electricity
