下面每个句子有一处错误.请改正过来

下面每个句子有一处错误.请改正过来
1.What are you going to do?I'm going to watering the flowers.
2.Look!Cindy is skiping on the playground.
3.Are your brother going to do the high jump?Yes,he is.
4.Whose hat is that?It's my brother.
5.When our National Day?It's on the first of October.