，熟悉分析过程，注意在构造表2时依据“操作符运算优先级和运算符的结合率”原则解决冲突。(2)思考：如要将程序改成SLR四则运算语法分析器，应如何修改文法3为文法4(文法4应还支持减除运算)。(3)思考：要将程序改成SLR四则运算语法分析器，应如何在该程序的基础上修改、增加代码。-Familiar with the process, analysis, pay attention to in the construction of Table 2 for "with the operator priority of operations and operator of rate" principle to solve conflict. (2) think: if the program should be changed to SLR four operations should be how to modify the grammar parser, 3 to 4 (4 grammar grammar should also support the subtraction operation). (3) think: the program should be changed to SLR four operations parser, should how to modify, add the code in the program is based on.