The present-day English vocabulary grows very fast. Explain the

The present-day English vocabulary grows very fast. Explain the main sources of new words with examples.
【正确答案】：Generally, there are three main sources of new words. Rapid development of modern science and technology breeds new words like green revolution; social, economic and political changes bring about such words as fast food; the influence of other cultures and languages can be felt in such words as kungfu. (其他举例正确的也可给分)