عايز حل الجمله دى
 

Omar said to sara " you mustn't park here"

Omar told Sara that she wasn't allowed to park there.

طب لو عملتها كدا تنفع
Omar told sara that she mustn't have parked here

مظنش لان mustnot مبيجيش بعد have PP ومتنساش هير بتتحول زير

Omer told /ordered Sara not to smoke there .

omar advised Sara not to park there
omar told sara that she wasn't allowed to park there
omar warned sara to park there

omar told sara that she didn't have to park there.

omar warned sara from parking there

Omar told Sara that she wasn't allowed to park there.
Omar warned Sara of / against parking there.
Omar ordered Sara not to park there.
Omar forbade Sara not to park there.
warn from خطأ

مجرد رأي
 

اعتقد ان المعني انها لم تركن و لذلك مسالة استخدام blaming مش مطلوبة لكن اتفق مع الحلول السابقة

Omar told Sara that she wasn't allowed to park there


this is only acceptable because must here is used for prohibition , not for necessity, advice, or warning