There used to be some trees,______ there?

There used to be some trees,______ there? there used to be some trees in this field .完成反意疑问句 第10题 There used to be some trees by the lake,_________? 31.There ______ some houses near the river.A.were used to be There used to be some cities wall.的反义疑问句 There used to be a lot of pandas,_______ ______? there be 和used to 英语.there used to be There used to be many green trees in this area in the past . There used to be a lot of tall trees on that mountain,_____? 反义疑问句：There used to be a lot of trees here,____there?为什么可以用w There used to be a lot of trees.变为否定句