关于what is wrong with .....?

忘了用WAS 还是IS 了。总之我觉的是
I didn't know what wrong he is.
或
I didn't know what wrong he was.

I didn't know what was wrong with him.

主句中谓语用了didn't，所以宾语从句谓语be动词，也要用过去时was

正解I didn't know what was wrong with him.
在做宾语从句的时候,一定要注意关系代词在句中的成分.而这里"what was wrong "是主-系-表结构,很明显"what"作主语,所以顺序不用变.

语序变不变,关键是看关系代词在句中的成分!

是I didn't know（ what was wrong with him).括号内做宾语从句，而这个从句本来就是正确的主谓结构，这个what在从句中是做主语，你讲的没错。
宾语可以是个物，可以是个句子，我用简单的中文来说明一下，比如：我喜欢他。“他”就做宾语而且是个词；再比如：我喜欢他对人友好，“他对人友好”就是个句子，这个句子整体做了宾语，也就是做了宾语从句。

I didn't know what was wrong with him.
因为主句是I didn't know...
时态是过去时 所以从句也应该是与过去有关的时态
然后what is wrong with .....?
这类句子作为从句的时候保持原来的语序不变（这是一种例外）
所以就变成 I didn't know what was wrong with him.
绝对正确..

语序不变，注意时态，

what作主语

与此类似的还有waht is the matter
what is the trouble