هَلْ زَيْدٌ قَائِمٌ؟ is a nominal yes/no question. Hal does not put the subject or predicate into the accusative.
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Hal with a Nominal Sentence
The Two Interrogative Particles: Hamza and Hal
هَلْ زَيْدٌ قَائِمٌ؟ is a nominal yes/no question. Hal does not put the subject or predicate into the accusative.