s
cut _
cuts
ox _ _
oxes
ti _ _
tied
whist _ _
whistle
warm _ _ _
warmest
dog _
dogs
go _ _
goes
kne _ _
kneed
thist _ _
thistle
cold _ _ _
coldest
frog _
frogs
do _ _
does
caged
coup _ _
couple
bigg _ _ _
biggest
boat _
boats
rac _ _
races
ski _ _
skied
padd _ _
paddle
small _ _ _
smallest
germ _
germs
tub _ _
tubes
bak _ _
baked
fab _ _
loud _ _ _
est