Is this factory ____your father used to work many years ago?

Is this factory ____your father used to work many years ago? this is the factory.his father used to work this is the city It was this factory that my father used to work. 1.this is the factory ----------- i used to work David began to work in this factory 10 years ago(改为同义句） this is the place that i used to visit ten years ago和this is the factory where my father used to work. Is this the factory __________ he worked ten years ago? A and B came to this factory two years ago This is the classroom ___ I used to study in ten years ago.( My father ___(work) in the factory since three years ago. My father ___(work) in the factory since three years ago.答案是