How to add back one column back to testing part after testing model?

I built a model and finished testing. Now I want to add one column(id) back to testing part, also with the predicted results.

Highlighted yellow part is what I used for training(C2-C4,row 1-4), highlighted green part is used for testing(C2-C4,row5-6.) train/test

I expect to get the following: expected results