根据上下文的语法结构及所给提示填空，使短文连贯通顺。
People ____ (live) in different countries made different kinds of words. Today there are about fifteen hundred ___(language) in the world. Each contains many thousands of words. A very large dictionary, for example, contains four ___five hundred thousand words. But we do not need __ these. To read short stories you need to know only about two thousand words. ____ you leave school, you will learn only one thousand or more. The words you know are called your vocabulary. You should try to make your vocabulary ____ (big). Read as many books as we can. There are a lot of books ___ (write) in easy English. You will enjoy them. When you meet ____ new word, look it ____ in your dictionary. Your dictionary is your __ (much) useful book.