كَانَ الطَّالِبَانِ حَاضِرَيْنِ
Translation: The two students were present.
كَانَ: past incomplete verb.
الطَّالِبَانِ: dual nominative ism kāna, marked by alif.
حَاضِرَيْنِ: dual accusative khabar kāna, marked by yāʾ.
The grammatical roles stay the same; case endings change with the noun class. Not every nominative uses visible ḍamma or every accusative visible fatḥa.