protocol

n.礼仪，外交礼节；草案，协议

protean, protect, protect...from, protection, protectionism, protectionist, protective, protective custody, protectively, protector, protectorate, protege (fem 阴性作 protegee), protein, protein-rich, protest, Protestant, Protestantism, protestation, protester, protestingly, proton, protoplasm, prototype, protozoan, protozoon (also protozoan), protract, protracted, protraction, protractor, protrude, protrusion, protrusive, protuberance, protuberant, proud, proudly, Prov, provable, provably, prove,