What is the difference between 我做的决定 and 我的决定？
The difference of "the decision I made" and "my decision".
Why not 了 at the end? This is a decision that I made (completed), so why not 他认为我做了的决定很好？
He thinks i made a good decision.
I was marked wrong for not using 的. Why is it required in this position or at all?
And why not "他认为决定我做很好"?