DuoLingo widerspricht sich
- the first question: "I have once seen an elephant" is "Ich habe einmal einen Elefant gesehen"
- the second question: "Ich habe einmal einen Elefanten gesehen" is "I have once seen an elephant"
Fehler wurde von DuoLingo behoben ( 2012-09-05 )
Two things: The elephant is object, so it should be "Elefanten", which means that the first alternative is erroneous and the second is right. In your second window you show the right German form: "ich habe einmal einen Elefanten gesehen." You are suggesting, that DuoLingo is wrong about the position of "once". No, I think the only possibilities here are: Once, I have seen an elephant, I have once seen an elephant or I have seen an elephant once, but not your word order.