push-down的用法和样例：
词汇搭配
- push down 下推
- push-down register 后进先出寄存器...
- push-down nesting 下推嵌套
- push-down store 叠式存储器
- push-down tape 下推带
- stack push down 堆栈压入
- push-down list 后进先出表
- push-down stack 下堆栈
- push down queue 后进先出队列...
- push-down storage 后入先出存储器...
- push-down queue 下推队列, 下推排队...
- push-down automaton 排队式自动机...
- push-down transducer 下推翻译机
- push down storage 下推存储器, 后进先...
- push down stack 下推栈
- push-down memory 后进先出存储器...
- push-down transformer 下推变换器
