1. Do you like swimming and skating ?I like skating.
and 改为or
肯定句用and ,否定句和疑问句用or
2. Look! the boys running after the boll.
running 改为 is running
be+动词ing现在进行时的结构
3. my sister is thiner than me.
thiner---thinner 单词拼写错误

4. Nancy is five year older than her cousin
five year----five years五岁
5.My bag is the same as her
her 改为hers 相当于 her bag ,这里名词性物主代词
望采纳,谢谢!