- 变同义句。Peoplestillcouldn'tfindtheb
- still couldn't find the boy. 能不能变
The boy couldn't be found.
The boy hadn't be found.
The boy was still missing.
- 意思都是差不多的,只是主谓不一样而已
The boy couldn't be found.
The boy hadn't been found.(这里应该用完成时)
The boy was still missing.