1. Words ending in e, preceded by a consonant, usually drop e on taking a suffix beginning with a vowel.

movemoving
believebelieving
conceiveconceiving
receivereceiving
achieveachieving

2. Words ending in ue drop e on taking a suffix.

arguearguing
fatiguefatiguing
Exception: vague, vaguely, vagueness.

3. Words ending in e retain e on taking a suffix beginning with a consonant.

movemovement
largelargely
hoarsehoarseness
peacepeaceful
sensesenseless
wholewholesome
remorseremorseless
advertiseadvertisement

4. Words ending in ce or ge retain e on adding able, ably, or ous.

changechangeable
couragecourageous
noticenoticeable
outrageoutrageous

II. For doubling the final consonant.