Rule 1: 1. The four narrative past tenses
The perfect reports a completed event: عَبَرْنَا. كَانَ + imperfect describes a background state, a habit or an action in progress (lesson 153): كَانُوا يُصْلِحُونَهَا. كَانَ قَدْ + perfect is the pluperfect, an event before the main time of the story: كَانَ الْمَطَرُ قَدْ نَزَلَ. أَخَذَ، صَارَ، جَعَلَ + imperfect mark the beginning or onset of an action: أَخَذَ يَلْتَوِي 'it began to wind'.
خَرَجْنَا مِنْ صَنْعَاءَ قَبْلَ طُلُوعِ الشَّمْسِ.
kharajnā min ṣanʿāʾa qabla ṭulūʿi sh-shamsi
We left Sanaa before sunrise.
Simple perfect: the event.
كَانُوا يُصْلِحُونَ الْجُدْرَانَ بَعْدَ كُلِّ مَطَرٍ.
kānū yuṣliḥūna l-judrāna baʿda kulli maṭarin
They used to repair the walls after every rain.
Past habit.
كَانَ الْأَطْفَالُ قَدْ رَأَوْا سَيَّارَتَنَا مِنْ بَعِيدٍ.
kāna l-aṭfālu qad raʾaw sayyāratanā min baʿīdin
The children had seen our car from afar.
Pluperfect.
ثُمَّ أَخَذَ الطَّرِيقُ يَلْتَوِي وَيَصْعَدُ.
thumma akhadha ṭ-ṭarīqu yaltawī wa-yaṣʿadu
Then the road began to wind and climb.
Onset of a process.
صِرْنَا نَرَى السُّحُبَ تَحْتَنَا.
ṣirnā narā s-suḥuba taḥtanā
We came to see the clouds below us.