ما الفاعل في الجملة: "شرح المعلمُ الدرس"؟

This question tests the ability to identify the فاعل (subject/doer) in an Arabic verbal sentence.

In the sentence شرح المعلمُ الدرس (The teacher explained the lesson), the grammatical analysis is:

• شرح is the فعل ماضٍ (past tense verb), meaning "explained." The verb is not the doer of the action; it describes the action itself.
• المعلمُ is the فاعل (subject), the one who performed the action. It carries the ضمة (nominative marker), which is the required case for the فاعل.
• الدرس is the مفعول به (direct object), meaning "the lesson" - the thing that was explained.

The فاعل always comes after the verb in a verbal sentence (جملة فعلية) and is always in the nominative case (مرفوع). To identify it, ask: who performed the action? The teacher is the one who explained, making المعلم the فاعل.