which came first, the chicken or the egg?

which came first, the chicken or the egg? used to say that it is difficult or impossible to decide which of two things happened first, or which action is the cause and which is the effect先有鸡还是先有蛋？〔用于表示先后或因果难以区分〕

• quantum-wave equation
• perpent
• Distrito Federal
• sepg
• hypersexual
• from first to last
• (be / feel) like a fish out of water
• courante
• semantic error
• westernism
• leptomeningitis
• gold leaf
• Yorkshire puddings
• a nail in it's coffin
• corporatises
• sage hens
• Poupart's ligament
• scratch brushing
• yarn-dye
• animal myth
• rubicons
• squawmish
• boyhood
• intrinsic semiconductor
• never better
• fellowship
• at the moment
• Atomic Veterans
• wild hog
• n.c.a.a
• all of
• Stoker, Bram
• faintest
• Domestos
• with one's head in the clouds
• reciprocal observations
• play at
• extra-special
• typothetae
• jagannaths
• neandertals
• daffier
• self-deceivings
• automatic writings
• it won't kill you us
• lathiest
• ex-services
• keep back (from sb/sth)
• mother cell
• riegel
• arabinosides
• snow accumulation
• neurofibromatosis
• condomaximium
• Dalman plate technique
• Siqueiros, David Alfaro
• sunlessness
• MBD
• juju music
• evergreen oak
• Merak
• laicisations
• security police
• pressure tank
• calorimeters
• ennobler
• fishworm
• fool away
• triggerman
• stranskiite
• coronary disease
• boat necked
• thuliums
• underestimate
• short sales
• internal drift current
• Ochteroidea
• weather station
• nebular lines
• accrd
• transferrer
• swimmering
• price out of the market
• animalising
• high hurdles
• uproar
• Indias
• audio-cassette
• Hammett, Dashiell
• lemon verbena
• sulphidic
• Kilkenny cats
• american languages
• nonviscousness
• chondromucoid
• wiver
• focus on
• pluralized
• circumnutations
• indebtedness