Rule 1: 1. Perfect and imperfect in a narrative
The backbone of a story is the perfect: one completed event after another, usually linked by فَ and so, then or وَ and: نَامَ … فَخَرَجَ … وَلَعِبَ … فَقَامَ. The imperfect appears when a character speaks about the present or the future, or when the narrator states a general truth. The particle لَمَّا when with the perfect marks the moment at which the next event follows.
نَامَ الْأَسَدُ تَحْتَ الشَّجَرَةِ، فَخَرَجَ الْفَأْرُ وَلَعِبَ عَلَى ظَهْرِهِ.
nāma l-asadu taḥta sh-shajarati, fa-kharaja l-faʾru wa-laʿiba ʿalā ẓahrihi
The lion slept under the tree, then the mouse came out and played on its back.
Three perfects in sequence.
كَيْفَ يَقْدِرُ فَأْرٌ أَنْ يُسَاعِدَ أَسَدًا؟
kayfa yaqdiru faʾrun an yusāʿida asadan
How can a mouse help a lion?
Imperfect inside speech.
لَمَّا سَمِعَ الْفَأْرُ الصَّوْتَ جَرَى إِلَى الْأَسَدِ.
lammā samiʿa l-faʾru ṣ-ṣawta jarā ilā l-asadi
When the mouse heard the sound, it ran to the lion.