Mariḍa Khālidun. Aṣābat-hu ḥummā.
Khalid became ill. He contracted a fever.
Implied question: 'What happened to him?'
Najaḥa al-ṭālibu. Ijtahada ṭūla al-sanati.
The student succeeded. He worked hard throughout the year.
Implied question: 'Why did he succeed?'
The decisive criterion is contextual fit, not a mechanically inserted question.