想問下有咩ing form既verb特別d?

There are two mistakes in 回答者:TOMING88’s answer.

bite—bitting ~ wrong
ride--ridding ~ wrong

bitting ~ no such word in the dictionary.
Ridding ~ present participle of “rid”

ride – riding
rid (verb) – ridding
bite – biting

cite - citing
hide – hiding

Rule 1:
Double the final consonant when the final two letters of a word are a singular vowel letter followed by a consonant letter
.
sit – sitting (~ last two letter “it”. “i” is a vowel; “t” is a consonant)
get - getting
plan – planning
swim – swimming

Note: a, e, i, o, u are vowels. The rest are consonants

Rule 2:
In two- or three –syllable words, the rule for doubling is changed as follows:
Double the final consonant as described in rule (1), if the last vowel in the word is stressed (as in (A) below, but not if it it is unstressed (as in (B) below)
(A) admit – admitting, occur – occurring, prefer – preferring
(B) develop – developing, enter – entering, visit – visiting

exception in (B)
travel – travelling (British), traveling (US)
worship - worshipping (British), worshiping (US)

Rule 3:
Drop the silent e
write – writing
use – using

Don’t drop e if ending in –ee and -ye
dye – dyeing (Be careful: die – dying)

Rule 4:
Change –ie to –y- before –ing in the verb
lie – lying, tie – tying

Rule 5:
Be careful with words ending in –ic. Add “k” before -ing in the verb.
panic – panicking, picnic – picnicking, traffic – trafficking

That is all I can think of.

2013-05-16 01:38:58 補充：
意見者:小草 Thanks a lot.

Forget to mention the exception in Rule (1)

留意若從後數上來第二個字母是響音，但最後的字母是 y 或 w，則不會 double.
e.g. play --> playing
show --> showing

若連續兩個響音，亦不用 double
boil --> boiling

2013-05-15 12:45:39 補充：
ride 字，從後面數的第二個字母是 'd'，並非響音，所以當轉為 present participle 時，刪除字母e，所以不用 double:
ride --> riding
make --> making

not all t becomes a double t after verb in present participle in irregular verbs,it all depends:-
beat--beating
bite--bitting
bless--blessing
cast--casting
cost--costing (pronounced cosing')
hurt--hurting
let--letting
light--lighting
pre-set---pre-setting
put--putting
recast--recasting
ride--ridding
sell--selling
set--setting
shit--shitting
shut---shutting
sit--sitting
slit--slitting
smell--smelling
spell--spelling
spill--spilling
spin--spinning
spit--spitting
split--splitting
string--stringing
swim--swimming
tear--tearing
tell--telling
upset--upsetting
wed=--wedding
wet--wetting
win--winning
write--writing