改错并指出错误I wanted to know whether have they been to the Great Wall

I wanted to know whether they had been to the Great Wall
我这样改的原因是：
1、关于have been顺序的调整
这是因为在whether 后用陈述语序，而不用疑问语气。
更多例子：I don't know whether he can do it.我不确定他是否能完成
2、关于have 变成had
由于主句是wanted，已经表示了过去的时态，而又在讨论他们在我wanted to know这一过去动作之前，是否去过长城，过去的过去用过去完成时。

I wanted to know whether they have been to the Great Wall
宾语从句用陈述句语序

应改为I wanted to know whether they have been to the Great Wall.
whether引导know的宾语从句，因此应该为陈述句语序。

谢谢！

I wanted to know whether they had been to the GreatWall
宾语从句用陈述语气
主句用过去时态，从句还问“以前”，为以前的以前，用过去完成时
二三楼错

I wanted to know whether have they been to the Great Wall

我想知道他们是否去过长城。
I wanted to know whether they have been to the Great Wall or not.
或者
I wanted to know if they have been to the Great Wall.

I want to know whether they have been to the Great Wall.
I wanted to know whether they had been to the Great Wall.
注意：
1.句子前后时态要一致！