The teacher and his students knew nothing about the crack on the wall(idea) Neither..........

Not a single person, neither the teacher nor his students, knew about the crack on the wall.

The teacher and his students were completely oblivious to the crack on the wall.

None of them, neither the teacher nor his students, had any idea about the crack on the wall.

The teacher and his students were equally clueless about the crack on the wall.

Neither the teacher nor his students had any knowledge of the crack on the wall.