Question

There used to be lots of old city walls in beijing 的反意疑问句

Answer 1

There used to be lots of old city walls in beijing,usedn't there?

如果陈述句部分的谓语含有used to,其反问部分既可用use(d)n’t,也可用didn’t.例如：

There used to be some trees in this field,use(d)n’t / didn’t there?

You used to smoke a pipe,use(d)n’t / didn’t you?