context-free的用法和样例：
词汇搭配
- context-free grammar 上下文无关文法...
- context-free branching rule 上下文无关分支规则,...
- stochastic context-free grammar 随机上下文无关文法...
- context-free language 上下文无关语言...
- deterministic context-free grammar 确定性上下文无关文法...
- restricted context free grammar 受限上下文无关的文法...
- context-free programmed grammar 上下文无关程序文法...
- context-free parser 上下文无关语法分析程...
- context-free speech 上下文无关语言...
- context-free program 上下文无关程序...
- deterministic context-free language 确定性上下文无关语言...
- context free grammar 上下文无关文法...
- context-free grammar recognizer 上下文无关文法识别程...
