百度知道 - 信息提示

11, helping: enjoy doing sth. 12. arrival （用名词） 13. go 情态动词或助动词后跟动词原形。 14. healthy 用形容词 15. written 过去分词做定语。 11. applications，用名词 12. cheerful 用形容词 13 has seen 已经看了几遍了 14. introduced 15. is allowed

1.What are you doing? 2.Yes,she is. 3.The students aren't having an English class. 4.She is playing ping-pong now. 5.When are the children dancing? 6.What is she doing? 7.Is your brother playing basketball? 8.Are the boys… 9.… are talking about… 10What is…doing