IT means make the changes,and PROOFREAD it before you turn it in.
You would be amazed at the number of students who turn things in without checking it themselves.
oh k i thought it meant a rough copy
If nobody is available to proofread your work, you can do this yourself. After writing your material, put it aside for a day — at least several hours. (This breaks mental sets you might have that keep you from noticing problems.) Then read it aloud as if you were reading someone else's work. (Reading aloud slows down your reading, so you are less likely to skip over problems.)
If your reading goes smoothly, that is fine. However, wherever you "stumble" in your reading, other persons are likely to have a problem in reading your material. Those "stumbles" indicate areas that need revising.
Another option, if it is available on your computer, is to have the computer read it to you.
Once you have made your revisions, repeat the process above. Good papers often require many drafts.
I hope this helps a little more.