Plant Protection Products Directive植物保护产品指令 Pennies to Protect Police Dogs硬币来保护警犬 Pilot Production Program Definition飞行员的生产计划的定义 Point-To-Point Protocol Daemon点对点协定精灵 Per Person Per Day (travel pricing/expenditures)每人每天旅行定价/支出 Point To Point Protocol Daemon点对点协定精灵