Do not neglect your lesson lest you regret it. Lā is prohibitive, so tuhmil is jussive; fa-tandama is subjunctive through an implied an after causal fāʾ in the response to a prohibition.
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Case 4: Prohibition Followed by a Consequence
Advanced Parsing Workshop: Integrated Grammar
Do not neglect your lesson lest you regret it. Lā is prohibitive, so tuhmil is jussive; fa-tandama is subjunctive through an implied an after causal fāʾ in the response to a prohibition.