I often watch./ I'm watching TV.
He cleans his room every day./ He is cleaning his room now.
构成:
1-ing doing,going,sleeping,playing,eating,drinking,singing,watching,studying,flying,reading,jumping,laughing,raining,waiting,.
2.去不发音的e再加ing
writing,dancing,smiling,hiking,
3.末尾只有一个辅音字母的重读闭音节,先双写这个辅音字母,再加ing.
running,swimming,sitting,shopping,beginning,cutting,hitting,