21. 世界与环境 The world and the environment

（73）国家与民族 Countries and nationalities

America, South Africa, Mexico, Germany, Australia, Brazil, Canada, Egypt, India, Italy, Russia, Mongolia, Britain, England, Ireland, Scotland, Spain, Sweden, China, Japan, Portugal, Iceland, New Zealand, Thailand, France

（74）环境保护 Environmental protection

pollution, land use and quality, population growth, housing, the destruction of environment, the rapid development of economy and increase of population, ecological balance, stop the environmental pollution, smoke and harmful chemicals from factories and garbage from cities, Recycling of paper, steel, and plastics is important for helping protect our environment. denudation, catastrophe, greenbelts

（75）人口 Population

overpopulation, under population, urban/rural population, reproduction, increase, decrease, base, distribution, density, quality, statistics, birth control, monogamy, fertility, birth rate, natural growth, aging of population, census