The book also places اثْنَانِ and اثْنَتَانِ in this case class.
اثْنَانِ: two (masculine), nominative.
اثْنَيْنِ: two (masculine), accusative or genitive.
اثْنَتَانِ: two (feminine), nominative.
اثْنَتَيْنِ: two (feminine), accusative or genitive.
Notice: The rule concerns their grammatical forms as well as their meaning.
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Noun Case Classes: Type 5 — The Dual and Related Forms
The book also places اثْنَانِ and اثْنَتَانِ in this case class.
اثْنَانِ: two (masculine), nominative.
اثْنَيْنِ: two (masculine), accusative or genitive.
اثْنَتَانِ: two (feminine), nominative.
اثْنَتَيْنِ: two (feminine), accusative or genitive.
Notice: The rule concerns their grammatical forms as well as their meaning.