"Dompetmu diambil siapa?"

Translation: Your wallet is taken by whom?

[poompah]

Who took your wallet?
This is almost always going to be the used form of this sentence. The literal translation accepted is correct of course, but will almost never be heard or used in normal conversation.

[KamoSaru]

But if they put the English "Who took your wallet?", the learners would always translate it into "Siapa mengambil dompetmu?" and never have a chance to practice translating it into "Dompetmu diambil oleh siapa?". Literal translation is sometimes good for beginners.

[Jan320480]

agreed!

[Edward686454]

This. Also in other questions the literal translation is incorrect, so some consistency would be nice.

[JarrodMain]

'was' should also be accepted.

[tsuj1g1r1]

Is "oleh" optional or do you have to memorise which verbs take it and which don't?

[Rick392366]

Is "oleh" optional or do you have to memorise which verbs take it and which don't?

'oleh' is optional in this sentence.
'oleh' = 'by'

'oleh' is used in combination with di- verbs (passive).

[1CN5ijzC]

if we use "oleh" to identify the doer / person who do the verb, we can omit it

[SimonDyett]

Present continuous tense 'is' does not make sense as an answer. Should be past tense 'was'

[XavierLamb9]

Can "Your wallet is taken by who"? be correct too?

[Tim371925]

No. It must be "whom" if you use this construction.

[Mario_Fez]

Casually, yes. 99% of native English speakers never use "whom" in daily conversation. "My wallet was taken!" "By who?"

Formally, what @Tim371925 said. "Whom" is for the object (which is required after the use of the preposition "by"), and "who" is for the subject.

[TakeYoshim2]

The English example sentences must be considered to renew so as to be more appropriate English and current English.