a tough（或 hard） nut to crack

a tough（或 hard） nut to crack informal a difficult problem or an opponent hard to beat 〈非正式〉难以解决的问题; 棘手的事情; 劲敌。

• mucklucks
• qualified opinion
• jack up
• loaves
• spread-eagle
• sideed
• manual operation
• dangs
• mosh
• axisymmetry
• formalisms
• split ups
• reposer
• clinical neurologies
• e.d
• courting chair
• free school
• disk centrifuge
• seif
• sociol
• sissoos
• Aldo
• at the cost of ...
• denuding
• balance control
• Asbury Park
• Wieland, Christoph Martin
• out of harmony with
• millennially
• letter bomb
• ad hockery
• in the style of oracle
• Civ.
• emission tomography
• Babists
• embryoids
• exhibit
• push-in crime
• not know a person from Adam
• angle of static friction
• parsoness
• exhausted
• geometric abstraction
• Broken Hill
• iron nonacarbonyl
• deindividualized
• oldsters
• job-flow control
• perky
• instrumentalisms
• in half a shake
• agaricuss
• would-bes
• anticapacitance switch
• famuluss
• gag-reined
• middle-agehood
• have it on one's dancers
• bodiced
• pronominals
• bear up
• exterminating
• Cytophagaceae
• Os
• stand off and on
• seal weld
• gyrases
• Dunfermline
• put on (或wear)the motley
• hot configuration
• viral hepatitis
• virginium
• put / set sb's mind at rest
• cunning
• Harry
• macular
• caza
• Procaine Amide
• opossum shrimps
• series firing
• targas
• chromodynamic
• sharp-cuts
• toluic acids
• subtype
• advanced project
• don'ts
• Black Stream
• sit back on one's laurels
• Federal Register
• illustration
• overweighs
• exhaust valve
• advisedly
• stave in
• quarried
• winkling
• hash sth ↔ out
• scarlet clematis
• cowsonantally