Question

Поставьте сущ. в единственное число.
Aircraft,brothers-in-arms,brothers-in-law,cuckoos,deer,feet,flies,girl-friends,hairdos,keys,languages,leaves,lice,mice,Negroes ,parties,pianos,foofs,sheep,skies,taxes,taxis,theses,tomatoes,zeros.

Answer 1

Aircraft
brother-in arm (?)
-
-
deer
foot
fly
girlfriend
-
key
language
leaf
louse
mouse
-
part
piano
-
sheep
sky
tax
taxi
-
tomato
zero