Question

She knew they were having the same troubles that she had experience.中have为什么用having

Answer 1

She knew they were having the same troubles that she had experienced.中have为什么用having
they were having the same troubles 是一个宾语从句。宾语从句的谓语动词用【过去进行时】，意思是【她那时知道】他们那时【正遇上了】她曾经历过的麻烦。
如果我的回答对你有帮助，请及时采纳，谢谢！

Answer 2

强调她知道的时候他们正在经历同样的麻烦，所以用过去进行时。

Answer 3

were 属于 be 动词 are 的过去式，所以用 be doing 表示他们过去的那个时间刚好正在做某事

Answer 4

know sb doing sth 知道某人正在做某事。
她知道他们正在遭遇她所经历过的同样的麻烦

Answer 5

be后面有动词就要用动词ing形式呀。。。