كَيْ follows an action and tells the purpose for which it is done.
اِقْرَأِ الْقُرْآنَ كَيْ أَفْهَمَهُ
Read the Quran so that I may understand it.
The first action is reading. كَيْ أَفْهَمَهُ gives its purpose: understanding it. The first-group verb أَفْهَمَ ends in fatḥah.
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Kay, Idhan, Hatta and Purpose Li
كَيْ follows an action and tells the purpose for which it is done.
اِقْرَأِ الْقُرْآنَ كَيْ أَفْهَمَهُ
Read the Quran so that I may understand it.
The first action is reading. كَيْ أَفْهَمَهُ gives its purpose: understanding it. The first-group verb أَفْهَمَ ends in fatḥah.