What role does 成 (chéng) play in the sentence 我把十块美元换成人民币?
成 (into) is the result complement of the verb 换(change)

换 = change
换成 = change into
兑换 = exchange
兑换成 = exchange into


兑换 mostly refers to 'currency exchange'

换 can refer to exchange between anything.



In &quot;我把十块美元换成人民币&quot; (I exchanged $10 USD into RMB), '换' is obviously short for '兑换'. You can even replace '换' with '兑' (convert) and write: &quot;我把十块美元兑成人民币&quot; (I converted $10 USD into RMB)and the meaning would still be the same.