plummet         fall， plunge， steeply

plunge          move quickly， suddenly and with force

poise           be ready， be balanced， self-possession

ponderous       heavy， bulky， dull

posture         state， attitude； adopt a vain

poverty         state of being poor

precept         moral instruction

precipitate     throw smth violently down from a height

precursory      peliminary， anticipating

predilection    special liking， mental preference

preempt         obtain by preemption or in advance

premature       doing or happening smth before the right time

presage         warning sign

pristine        primitive

procrastination keeping on putting off

prodigious      enormous， wonderful