1. Don't just sit there! You should ____ (help) John with the work.
helping be helping have helped

2. I want to meet him at the airport. When will he ____ (arrive)?
have arrived arrived be arriving

3. I may ____ (go) to England next year.
have gone be going going

4. He really must ____ (leave) now, or he'll miss his bus.
be leaving is leaving be leaves

5. How long will they ____ (work) at the hotel?
have working be working are working