帮忙分析一下这个句子的语法

Question

There are lots of changes happened during the 1st two week in each term.

为什么在这用happened ，是什么词性？请尽量多分析，谢谢！

Answer 1

happened 是从句里的动词 后面的是定语从句
There are lots of changes （which/that） happened during the 1st two week in each term
后面是修饰限制前面的changes的

Answer 2

其实这在英语中是very common的,这个动词的过去分词作定语,类似的我们可以说,There is a book wrote by Steven Huoking .

Answer 3

动词的过去分词做后置定语，修饰“变化changes”.

参考资料：u