---Do you want a lift home? ---It’s very kind of you, but I have a much late in the office. I overslept this morning because my morning clock _______. 

When the old man_____to walk back to his house，the sun____itself behind the mountain．

— Has Tom finished writing his essay today? — I have no idea. He ______ it this morning. 

The old man was taking a walk, ____ by his grandson. 

The central heating system of this office building is down and several workers ______ it right now.