Answer :
Can we buy wisdom?
Extra Information :
Normal structure of interrogative sentence in active voice starting with modals is
- Modal + subject + verb + object ? (Active Voice)
Ex: Can she cook the food? (Active Voice)
(Here 'she' is subject, 'cook' is V-3 verb and 'the food' is object.)
While changing the sentence into passive, this structure becomes
- Modal + subject + be + V-3 + by + agent ? (Passive Voice)
Ex: Can the food be cooked by her? (Passive Voice)
(Here 'The food' becomes subject in passive voice, 'cooked' is V-3 (past participle) of cook, and 'her' is agent (doer).