كان and its sisters (كان وأخواتها) are a group of incomplete verbs (الأفعال الناقصة) that enter upon nominal sentences to add a sense of time or condition. Unlike إنَّ which changes the subject to accusative, كان keeps the subject in the nominative case (اسم كان — marfoo') and changes the predicate to the accusative case (خبر كان — mansoob).
كان and Its Sisters
- كَانَ (kaana): Was/used to be. كَانَ الجَوُّ جَمِيلًا (The weather was beautiful).
- أَصْبَحَ (asbaha): Became (in the morning). أَصْبَحَ الطَّالِبُ مُسْتَعِدًّا (The student became ready).
- أَمْسَى (amsaa): Became (in the evening). أَمْسَى الجَوُّ بَارِدًا (The weather became cold in the evening).
- ظَلَّ (zhalla): Remained, continued to be. ظَلَّ الوَلَدُ وَاقِفًا (The boy remained standing).
- بَاتَ (baata): Became (at night)/spent the night. بَاتَ المُسَافِرُ تَعِبًا (The traveler spent the night tired).
- صَارَ (saara): Became. صَارَ الطَّالِبُ مُعَلِّمًا (The student became a teacher).
- لَيْسَ (laysa): Is not (negation). لَيْسَ الأَمْرُ صَعْبًا (The matter is not difficult).
- مَا زَالَ (maa zaala): Still is/continues to be. مَا زَالَ الطَّالِبُ مُجْتَهِدًا (The student is still hardworking).
How They Change the Sentence
Compare: الجَوُّ جَمِيلٌ (The weather is beautiful — both marfoo') vs. كَانَ الجَوُّ جَمِيلًا (The weather was beautiful — الجو stays marfoo', but جميلًا becomes mansoob). The shift of the predicate to accusative is the defining grammatical feature of these verbs.
These verbs conjugate normally for tense and person. كَانَ can become يَكُونُ (present) or كُنْ (imperative). When conjugated, they still have the same effect on the nominal sentence they enter: يَكُونُ الجَوُّ جَمِيلًا (The weather will be beautiful). This makes them a versatile tool for expressing states across different tenses.