ne不是加上去的。
done是do的过去分词。用于现在完成时，过去完成时或被动语态。
Have you done your homework?
He said he had done his homework.
There is nothing to be done.
ＤＯ的过去时态．
done是do的过去分词,在过去过去完成时和被动语态时要把do变成done.
done是do的过去分词形式，用于所有形式的完成时。在口语中，可以单独使用，表示决定做的意思。
do did done分别是do的过去式和过去分词,不是随便加的