动词的—ing形式的构成
（1）一般在动词原形末尾加—ing。例如：work—working, study—studying.
（2）以不发音的字母e结尾的动词，先去掉e，再加—ing。例如:have—having, live—living.
（3）以重读闭音节结尾的动词，如结尾只有一个辅音字母，应先双写出这一字母，再加—ing。例如：run—running, stop—stopping,
forget—forgetting, begin—beginning。
（4）以ie结尾的动词，变ie为y，再加—ing。
练习
一、写出下列动词的ing形式
walk jump watch lie play
sing smoke dance drive run
swim sit tie read eat
二、用现在进行时完成下列句子:
1. ______you__________(fly) a kite? Yes,_______.
2. ______you___________(sit) in the boat?
3. ______he_____________(talk) with me?
4. We_______________(play) football now.
5. What_________you__________(do)?
6. I_____________(sing) an English song.