I read it in the text below:

Cannot is the correct form in almost all cases. The only (very rare) exception is in sentences like "You can do it, or you can not do it"—in other words, where the two words have their separate meanings ('are able not to'). In the normal sense ('not able to'), it is always one word. Anyone who tells you different is trying to get you red-penciled.

What does it mean? Is it a phrase or expression?

  • 2
    It's a reference to the stereotypical teacher's red pencil that they use to mark things wrong on a student's paper.
    – Jim
    Commented Apr 27, 2013 at 22:48
  • 1
    <comments removed> Please don't carry out extended discussion unrelated to the question in comments. If you have a concern about comments containing partial-answers, you're welcome to bring it up on meta. I've moved the comments to a chat discussion here. Thank you.
    – WendiKidd
    Commented Apr 28, 2013 at 23:22

1 Answer 1


In the US, at least, teachers traditionally corrected papers with a red pencil.* (Today it's a red ballpoint, or a Comment in MS Word .)

(Newspaper copy-editors, however, traditionally corrected with a blue pencil, which would not show up in a photo-lithograph. Later, when copiers came into use, they shifted to red pencils, until computer typesetting enabled them to ruin correct your copy without markup. Today of course, newspapers cannot afford copy-editors.)

So your source is saying that to spell it as two words invites bad marks, and urging you to ignore advice to the contrary.

* My father corrected papers with a blue fountain pen, but he taught at a university. And since no one could read his handwriting anyway it didn't matter.

  • So Is it a phrase from pasts? Commented Apr 27, 2013 at 23:18
  • @PersianCat Oh, it's not dead, and it may survive technological obsolescence - like the word font, which almost never has almost anything to do with melted metal any more. Commented Apr 27, 2013 at 23:58
  • I don't think I've heard "to be red-pencilled" used in this way in British English, but the tradition of marking with a red pen/pencil certainly does exist here to an extent that I would immediately understand the phrase. In fact it goes as far as some teachers deliberately marking with a non-red (often green) pen because they think the tradition is too confrontational. Commented Nov 2, 2015 at 17:28

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .