My father is usually on _______ duty in his office every _______ few days.
I'm sorry I didn’t phone you,but I've been very busy_____ the past couple of weeks.
---Are you going to Tom’s birthday party?---________.I might have to work.
He had his camera ready ____he saw something that would make a good picture.
Look over there--- there’s a very long,winding path _____up to the house.
I'm afraid he’s more of a talker than a doer, which is ____ he never finishes anything.