② Nepali grammar rules
1. The -एको + छ pattern
गरेको छु (I have done it) / पढेको छु (I have read it) / गएको छु (I have gone; I have been there) connect a completed action with a present result or experience.
Compare simple completed गरेँ with the compound गरेको छु (I have done it).
2. Respectful -नुभएको
Compare उहाँले पढ्नुभएको छ (he/she has read it, respectful) / उहाँ जानुभएको छ (he/she has gone; has been there, respectful).
Respect is marked in -नुभएको; the basic respectful perfect here ends in छ.
This is not formed by inserting the finite present जानुहुन्छ.
3. Agent marking
मैले किताब पढेको छु (I have read the book) has a transitive agent; म नेपाल गएको छु (I have been to/gone to Nepal) has an intransitive subject.
Compound completion preserves the distinction in subject marking.
4. Experience and frequency
पहिले, एक पटक (once), धेरै पटक (many times) can specify experience/frequency. नेपाल गएको छु (I have been to/gone to Nepal) can express experience or a present-relevant result; it does not invariably assert that the speaker is currently in Nepal.
5. Not yet and never
अझै गरेको छैन (has not done it yet) means not yet completed; कहिल्यै गरेको छैन (has never done it) means never done.
Negate the auxiliary with the छैन family, keeping the participle.
Personal forms include गरेको छैनँ (I have not done it).
A reference table for comparing personal forms