关于if的定语从句他们认不出他们看出的东西是否是个钱包?是不是应该说：They couldn't recognize i

关于if的定语从句
他们认不出他们看出的东西是否是个钱包?
是不是应该说：They couldn't recognize if what they saw was a wallet.
变成定语从句：They saw something they couldn't recognize if was a wallet.