Behind the factory there used to _________ much waste,______

Bhind the factory there used to (1 )much waste,( 2 1 have还是b Now he works in the factory _________ his father used to wor There used to be _________ near the river. The government forbad the chemical factory to pour waste int 改错1.There used to be a shoe's factory near the park.2Great c 第10题 There used to be some trees by the lake,_________? 1.this is the factory ----------- i used to work the factory where my father used to work. She used to work in the factory改为同义句, there used to be a shoe factory over there,usedn't there? There used to be a factory,wasn't there?这句话对吗? 31.There ______ some houses near the river.A.were used to be