I am so angry because I haven’t received the things that _______ (order) online a month ago
问题描述：
I am so angry because I haven’t received the things that _______ (order) online a month ago
答
were ordered
如果 things 后面没有接that 的话 就是ordered 此时,ordered作后置定语修饰things 表示被动 因为things是被 order（定制）的
但是这里有接that 那后面就变成一个that 从句了 在这个从句中things是作主语的 那么需要BE动词 were