they don't know they have lost the purse 这句话对不对

they don't know they have lost the purse 这句话对不对
they don't know they have lost the purse 这句话对不对

they don't know they have lost the purse 这句话对不对
they don't know they have lost the purse
没问题
他们不知道自己已经丢了钱包

They don't know that ...后面不变，貌似定语从句，少了that也应该没问题。