请问单词“chat"的doing形式是什么?

chatting
动词加ing变化形式只有三种,都弄明白吧：
1、大多动词直接在词尾加-ing,比如：go-going,work-working,study-studying,look-looking,do-doing,eat-eating,play-playing,read-reading,wash-washing,plant-planting,borrow-borrowing,pick-picking,paint-painting,cry-crying,took-tooking (v.拿,占领,接受） climb-climbing
2、有的以不发音的e字母结尾的动词,要去掉e再加-ing,比如：make-making,write-writing,skate-skating,close–closing,come-coming,make–making,take-taking,have-having,dance-dancing,
smile-smiling,ride-riding,become-becoming,
若结尾的e 发音,就不能去掉,如：see-seeing
3、以重读闭音节结尾,末尾只有一个辅音字母的动词,要双写这一辅音字母,再加-ing.例如：run-running,swim-swimming,get – getting,sit–sitting,put–putting,begin–beginning,hit-hitting
stop-stopping
如果结尾是元音字母加辅音字母组合,就直接加-ing.比如：drawing,playing