Keeping or dropping a final e
adding ing or ly to the end of words with an unpronounced or silent e,
you drop the e if the ending begins with a vowel. You keep
if the ending begins with a consonant.
Examples: advise + able = advisable, force + ible = forcible,
and care + ful = careful
Exceptions: dye + ing = dyeing, shoeing, and mileage.
Exception: the final e is kept after a soft c or g as in
courageous or changeable.
the final e is dropped before an ending beginning with a
consonant, when the e is preceded by another vowel as in argue + ment =
argument, true + ly = truly, and due + ly = duly.