4. Was the chief engineer showing the plants to the workers?  .............................................................................................................................................................................. 5. Were they asking that question?  .............................................................................................................................................................................. 6. Is Mary cutting the cake with a sharp knife?  .............................................................................................................................................................................. 7. Will they hold the meeting tomorrow?  .............................................................................................................................................................................. 8. Must they have learnt English words?  .............................................................................................................................................................................. 9. Has anyone ever treated the boy with such kindness?  .............................................................................................................................................................................. 10. Had they fastened him to the tree?  .............................................................................................................................................................................. 11. When does she often take her dog for a walk?  .............................................................................................................................................................................. 12. What did the manager ask new employees?  .....................................................................................................................................................................