向老师请教：tobetaught在下句中是否是不定式的被动语态做表语?为什么不直接用wastaught呢?theproblemforherwastobetaughtbytendifferentteacher.

　　向老师请教：tobetaught在下句中是否是不定式的被动语态做表语?为什么不直接用wastaught呢?

　　theproblemforherwastobetaughtbytendifferentteacher.