1·I have been skating for two hours （改为一般疑问句）
（have）you（ been ）（ skating ）for two hours?
2·He has been working since an hour ago.(改为否定句)
He （ hasn't）（ been ）（working ）since an hour ago
3·He ran for three hours.（对划线部分提问）
（ How ）（ long ）（ did ）he （ run ）
4·Jim got his favorite book on Children’s Day.（对划线部分提问）
（ when ）（did ）Jim （get ） his favorite book?
5·I have been collecting leaves for two years.（改为同义句）
I have been collecting leaves( since )(two )(years )(ago )