"He participated in the competition a month ago."

Translation: 他一个月前参加比赛了。

[6Pup5]

参加 is a verb, the 了 should be after 参加, not 比赛

[wclearn]

Agreed

[PeterOthag]

Exactly. I put that in and I got it wrong... I'm pretty livid atm lol. I'm native Chinese and, it aint too far of a stretch to say that it's kinda outrageous that I'm being denied the rights of my own language

[julykix]

他一个月前参加比赛了 = he has already competed (so he doesn't need to this time)
他一个月前参加了比赛 = he participated in a competition a month ago (the competition could still be going on)

[colinmcw]

This is a good simple way to explain the craziness of "le." You're a better teacher than Duolingo right now, julykix -- just gave you a Lingot :-)

[LlamaScota]

Shut up and take my lingots!

[beaudanner]

他一个月前参加比赛了。If you're going to force “了” at the end the translation should be. He HAD participated in the competition a month ago. Seeing as how you mark every other thing wrong for inconsequential changes.

[Gabrielle145359]

Since this is a past action, the 了 can go directly after the verb, or at the end of the sentence. Both should be accepted.

[JungleZL]

Wow as a native speaker I can still learn something new!

[fourthwall1]

i think duolingo is wrong or failed to accept other natural answers. So you might not have learned anything new here.

[duckmaestro]

Can the sentance start with "一个月前"?

[rao245234]

I think you can but the sentence has to be 一个月前他参加了比赛 instead of 一个月前他参加比赛了