20．Language is always changing and developing．This isn't a bad thing．If English hadn't changed for a long time，we won't have words to describe telephones，washing machines，computers or some other new things．
Language changes for several reasons．First，it changes because the needs of its speaker change．New technologies，new products，and new experiences need new words to express them clearly．Another reason for change is that different people have different language experiences．People use different sets of words and expressions，because they have different ages，jobs，education levels（水平） and so on．
How does language develop then？On the one hand，many of the languages changes begin with young people．When young people communicate with others of their own age，their language grows in grammar，words and expressions that are different from the older people's．Some have a short lifetime but others can influence the language for long．On the other hand，we get new words in many different ways．We borrow them from other languages，we create them by making words shorter or combining words and we make them out of proper names．
Languages that don't change over time are considered dead languages．The fact that English changes so much shows that it is alive and well．
71．What does the writer think of the change and developmentof language？
He thinks it isnot a bad thing．
72．Why do people use different sets of words and expressions according to the passage？
Because theirages，jobs and education levels are different．
73．How many reasons for language change are mentioned in this passage？
The writer mentionstwo reasons．
74．How do young people help develop language？
They do it when theycommunicate with others of their own age．
75．What is considered a dead language according to the passage？
The one thatdoesn't change over time is considered a dead language．
