A Hundred and One Rules in Arabic Grammar!
- The Sun Letters. ===================
Due to a Phonological rule, the /ل / sound of the definite article is assimilated by any of the following sun consonants. Therefore, you need to use Shadda to replace the assimilated /ل /. The Sun Letters are:
**ت ث د ذ ر ز س ش ص ض ط ظ ن الدَّرسُ**