سُئِلَ الْمُشْرِفُ: «مَاذَا رَأَيْتُمْ؟» فَقَالَ: «الْقَمَرَ».
The supervisor was asked, “What did you see?” He replied, “The moon.”
The question already supplies the verb raʾā. Therefore the accusative answer al-qamara can be expanded as raʾaynā al-qamara (“We saw the moon”). This is ījāz al-ḥadhf: an omitted element is recoverable from an evident clue.
Outside that exchange, the isolated accusative could be unclear. Ellipsis is rhetorically successful only when the missing sense is sufficiently recoverable.