لَقَدْ فَهِمَ الطَّالِبُ الدَّرْسَ
The student certainly understood the lesson.
Step by step:
● لَ adds further emphasis.
● قَدْ comes before the past verb.
● فَهِمَ is the past-tense verb.
● الطَّالِبُ is the subject.
The new example applies only the rule already taught here.