I do not understand the difference between telah and sudah since they both refers to ‘have’. I also do not understand the difference between betulkah and benarkah, are they interchangeable?
Here are my replies:
Telah is have with a completed sense
So if adik telah merokok pada 1978
He may not be doing so
Sudah is have with an open ended sense
So if adik sudah merokok pada 1978
He may still be smoking now (if he is still around)
Benar is true
Betul is correct
I used betulkah and translated it as is it true in the lecture because if it is correct implies that it is true.
Hence I used the concept of Correct entails truth in my translation
If that gets in the away of your comprehension you may change it to is it correct