说明：  编制一个递归下降分析程序，实现对词法分析程序所提供的单词序列的语法检查和结构分析。 利用C语言编制递归下降分析程序，并对简单语言进行语法分析。
(The preparation of a recursive descent parser, lexical analyzer to achieve the sequence of words provided by the syntax check and structural analysis. Use of C language compiled recursive descent parser, and parsing simple language.)