Positive form(肯定式结构): 主语+ am/ is /are +动词-ing形式. Negative form(否定式结构): 主语+ am/ is /are not+动词-ing形式.
Question form(一般疑问句结构): Am/ is /are +主语+动词-ing形式
答语
Yes,主语(人称代词) +be. No,主语(人称代词) +be not.
Positive form(肯定式结构): 主语+ am/ is /are +动词-ing形式. Negative form(否定式结构): 主语+ am/ is /are not+动词-ing形式.
Question form(一般疑问句结构): Am/ is /are +主语+动词-ing形式
答语
Yes,主语(人称代词) +be. No,主语(人称代词) +be not.