what is the trouble 在宾语从句中语序变不变?

what is the trouble 在宾语从句中语序变不变?
what is the trouble 在宾语从句中语序变不变?

what is the trouble 在宾语从句中语序变不变?
what's the trouble
what's the matter
是宾语从句中特殊的两个结构,语序不变的.

要改成陈述
what the trouble is

宾语从句都要改成陈述句语序.