"I went running for thirty minutes this morning."
To be fair to the course makers, I think they just haven't updated all of the correct answers yet, and that's part of the beta testing process which it's currently in. I'm also reporting lots of correct answers that should be accepted, hopefully in a few months they'll all be allowed as long as we keep reporting them. I agree though, it's quite frustrating at the moment.
I'm no native speaker so I might not be 100% correct. Please correct me if you read this and know better.
As far as I know you can't add an adverb or a time complement after a particle verb like 跑步， the qualifier of the action can only be place right after the verb character (跑 in this situation). apparently a solution to this problem is to put the second verb particle at the end following 的. (sounds familiar, german learners? )
The other way I know (although I don't know if it works here is to reduplicate the verb character like in the sentence 他游泳游得很快
But as I said I'm not sure if 早上我跑步跑了三十分钟 is correct. Does someone know?
I used an online translation tool. The original answer was 'I ran for 30 minutes this morning'. Your answer above was 'I run for 30 minutes in the morning'. It appears 了 was used to emphasize 'run' and not to mean it was a concluded action.
Every explanation helps. I was only looking at it as vocabulary and not a particle verb. Thank you.
I am still learning Chinese, so a native speaker would be the expert. However, you can put 了at the end. As I have the same questions, I use an online translation tool to try the various phrases. Your version translated to 'I ran 30 minutes in the morning'. Basically the same meaning.