给出非终结符的FIRSTVT和LASTVT集。画出算符优先关系表。给定符号串判定是否是文法中的句子，分析过程用计算机打印出来。-website is not the end of the FIRSTVT and LASTVT set. Ingenuous operator precedence table. Series set to determine whether the symbol is the grammar of the sentence, the analysis process