Answer the following questions. Your answers should be clear and short.What are the three main sources of new words in present-day English vocabulary? Match the following expressions with the three sources as examples.“green revolution", “fast food”，‘the fourth world”，“Mao jackets”, “open heart surgery ”
GENERALLY, THERE ARE THREE MAIN SOURCES OF NEW WORDS:（1）THE RAPID DEVELOPMENT OF MODERN SCIENCE AND TECHNOLOGY, E.G. GREEN REVOLUTION,OPEN HEART SURGERY. （2）SOCIAL, ECONOMIC AND POLITICAL CHANGES, E.G. FAST FOOD, THE FOURTH WORLD.（3）THE INFLUENCE OF OTHER CULTURES AND LANGUAGES, E.G. MAO JACKETS. 
