The affixes laṅ (Imperfect Tense) and liṭ (Perfect Tense) come after a verb (in expressing a past time not belonging to the current day and unperceived by the speaker) when the past referred to is recent and the sentence is interrogative.,
This sutra also qualifies the words भूत, अनद्यतन and परोक्ष understood in this sutra. The word प्रश्न means 'what should be asked'; and आसन्नकाल 'time close at hand': As, some one may ask another, अगच्छत् देवदत्तः, or जगाम देवदत्तः 'did Devadatta go or has Devadatta gone (just now)'? अयजद् देवदत्तः or इयाज देवदत्तः 'Did Devadatta sacrifice or has Devadatta sacrificed'?
Why do we say 'in asking question'? Otherwise there would be Perfect tense only. As, जगाम देवदत्तः 'Devadatta has gone'.
Why do we say 'when the past time referred to is imminently recent'? Observe भवन्तं पृच्छामि, जघान कंसं किल वासुदेवः 'I ask you, did Krishna indeed kill Kansa in days of yore'.,