一选择题 关于it used to be .... 麻烦帮看看 谢谢

In my opinion , life in the 21st century is much easier than ___________.
A it used to be B that used to be
答案是A B 错在哪里呢 ？

关于used to一问 选择题：What was it __ made our area different from what it used to be? It is a 高一物理选择题 关于used to 中的 used it is used for writing 关于高一英语选择题 一道关于it, this, that, so的选择题 还是关于高一英语选择题 关于with用法的一选择题 关于used to 的问题