Answer:
[tex] \boxed{ \sf{ Sabin \: did \: not \: sleep \: at \: 9 \: pm.}}[/tex]
Explanation:
Given sentence,
Sabin slept at 9 pm.
To change this sentence into negative, add did not after the subject .
Sabin did not sleep at 9 pm.
Note: While changing positive sentences into negative, V² takes did ( V² = did + V¹ )
Hope I helped!
Best regards! :D
