1.普通动词：直接 ing;
think---thinking sleep---sleeping study---studying
speak---speaking say---saying cry---crying
2.以不发音的e结尾的动词：去掉e再加ing，去e ing
wake---waking make---making come---coming
take---taking leave---leaving have---having
dance----dancing ride----riding write---writing
3. 以重读闭音节结尾，呈现“辅，元，辅”结构的动词，先双写末尾的辅音字母，再加ing
stop---stopping sit---sitting run---running forget---forgetting
begin---beginning cut---cutting get---getting hit---hitting set---setting swim----swimming fit---fitting dig---digging shop---shopping put---putting travel---travelling(可双写也可不双写) refer---referring prefer---preferring
4. 以ie结尾的动词，把ie改为y ，再加ing lie---lying die---dying tie---tying
