"What can I do?"
Translation:Apa yang dapat saya lakukan?
So the construction "apa yang" is followed by subject-verb inversion?
In a sentence like this, 'apa yang' is followed by the passive voice (passive type 2).
It's similar to the second example shown here :
Apa, Siapa, Tips & Notes, Addendum
The question can also be like this :
Saya dapat melakukan/lakukan apa ?
'apa' is at the end of the sentence.
When 'apa' is moved to the front, it becomes "apa yang", followed by the passive voice (type 2).
Apa yang dapat saya lakukan ?
In a sentence like this (passive type 2), nothing comes between the agent/actor and the verb.
Therefore, the following sentence is grammatically incorrect, because dapat comes between the agent/actor and the verb:
Apa yang saya dapat lakukan