1.The film has been on for half an hour.
2.How long has (此处楼主忘打主语) been in the Party?
或 How long has (此处楼主忘打主语) been a member of the Party?
3.The bus has been away for ten minutes.
4.Mr Green has been in this city since 1998.
5.We have known each other for a year.