be an unknown quantity

be an unknown quantity if someone or something is an unknown quantity, you do not know what their abilities are or how they are likely to behave未知的人（事物）

• democrats
• staghorn sumacs
• production rate
• married print
• light filter
• n-connected graph
• sangar
• isocyanide
• lock-in amplifier
• immerses
• signorinos
• Prussianizes
• reinscribe
• overhaulers
• Guenevere
• bass reflex
• doughfoots
• typical!
• feminine rhyme
• embassage
• Stokowski, Leopold Antoni Stanislaw
• photophone
• single-strand binding protein
• Armand
• Zosimus, Saint
• transputer
• as the spirit takes one
• hygr-
• roastingly
• conglomerater
• mushy
• hemangioblastomas
• cutleries
• chassis
• floating plant
• high-risest
• bearing walls
• torula
• invest ... with
• fire door
• bawlers
• averaging device
• amnions
• turbostratic structures
• preplant
• Araneae
• basiliscan
• cambric teas
• rowel
• SS-N-2
• pilies
• conservation of orbital symmetry
• hot cross bun
• precipitates
• dataries
• have a preference for
• zoomancy
• clinometry
• albatross
• degree day
• of ... choice
• bestrewed
• cakes and ale
• china plates
• the pink of perfection
• Finsen, Niels Ryberg
• rewardings
• henchmen
• natriuretic
• dry-tape fuel cell
• kedgers
• unforgiving
• cloudy
• dye laser
• let go (of sb/sth)
• lemon pudding
• surah
• Bobing
• klydonograph
• doronicum
• mandragoras
• noma
• be a household name / word
• by all appearance s
• kingwoods
• crop out
• ritzily
• urial
• Geritol generation
• equids
• organography
• bluster down
• hew to
• telephone set
• paradoxical reaction
• as like as an apple to an oyster
• maxillary sinus
• hydrowire
• Edessan
• pledget