Word-Processing Errors
If you write on a computer or word processor, you'll need to look out for leftovers from your cutting and pasting. More often than not, you don't get rid of all the old stuff when you paste in something new. The sentence leading up to what you just pasted in could be worded for the old version, and no longer make sense. Or you might have left behind actual pieces-words, parts of words, a comma-from the part you cut out.