What“s the trouble?=What's wrong?
What 是主語，is the trouble是系表結構作謂語
所以What"s the trouble?做賓語從句不需要作語序的調整。
如：I/d like to know what is the trouble.
2.根據上下文或具體語境，the trouble也可能是主語。比如原話是The trouble is that .........
就that從句提問也是What“s the trouble?
這時，它用作賓從就要改成陳述句語序:The trouble is what
把What放到句首做引導詞。如：I‘d like tiknow what the trouble is.