to prefer
prefered, prefering
preferred, preferring
to differ
differed, differing
differred, differring
to defer
deferred, deferring
defered, defering
to refer
referred, referring
refered, refering
to buffer
bufferred, bufferring
buffered, buffering
to transfer
transferred, transferring
transfered, transfering
to infer
inferred, inferring
infered, infering
to suffer
suffered, suffering
sufferred, sufferring
to offer
offerred, offerring
offered, offering
to confer
confered, confering
conferred, conferring