略举几例：
awake - awaken
bright - brighten
broad - broaden
cheap - cheapen
damp - dampen
dark - darken
dead - deaden
deaf - deafen
deep - deepen
fat - fatten
flat - flatten
fresh - freshen
glad - gladden
hard - harden
less - lessen
light - lighten
loose - loosen
mad - madden
moist - moisten
neat - neaten
quick - quicken
quiet - quieten
red - redden
ripe - ripen
rough - roughen
sad - sadden
sharp - sharpen
short - shorten
sick - sicken
slack - slacken
smart - smarten
soft - soften
steep - steepen
stiff - stiffen
straight - straighten
sweet - sweeten
thick - thicken
tight - tighten
tough - toughen
weak - weaken
white - whiten
wide - widen