When should I hit "UNDO"?

While I understand that the UNDO button can be very dangerous, I also understand that it save lots of headaches avoiding accumulating a bunch of trashy ghost reviews.

When should I press it? I was thinking of these reasons:

  • You misspelled one thing that you really shouldn’t have misspelled (typo)

  • The question was actually looking for the polite form and you put the casual, and the question marked it incorrect without warning you. This happens very frequently because the moment you type the first letter into the box, you will no longer be able to see if the question says [casual] or [polite]

  • You put a verb in the past tense, but it’s looking for the present tense and doesn’t warn you. Almost everything in English reads as if it’s in a past tense, so this happens more than I’d like it to.

When is the best time to hit that Undo button?


I mostly use it for typos because I’m more likely to make typing mistakes on my phone when I’m really sure of my answer and don’t check if I hit the buttons I intended to tap.

I can emphasize with your second point because the instant I start typing, I immediately forget what the grey text says, too. But I must have had better luck with politeness levels, because I don’t remember those to be particularly problematic.

Past/present is something that has to be learned though. English tenses don’t translate 1:1 to Japanese, so figuring out which one would be used in each given scenario is part of what we’re supposed to learn.


I use undo for things like past and present confusion when it’s not the thing being tested, though I feel a bit bad about it.

Though when I get the important part right and mess up by using 〜ます instead of 〜ました for example, I can’t help but feel that it would be counterproductive not to correct the mistake while the grammar point is supposed to ようにする or something.

This is not to say that the large variety of example sentences are bad, just that the yellow warning text could possibly be expanded upon to take things like this into account too.


I’ve used undo in all three of those situations, but you have to be careful of the politeness case. Make sure you don’t get into the habit of mixing casual and polite speech in unnatural ways.


It can and will, if you drop a report on sentences that are missing it!

I remember when those yellow warnings were first being added to the site; it was a huge confidence booster because instead of RED RED RED every time I wasn’t absolutely perfect, I started getting messages that were effectively saying, “hey, you’re on the right track here, there’s just one thing you haven’t accounted for yet!!”

It’s much more encouraging/reassuring to know that you’ve at least tried something sensible enough that the system caught it for you. So, I’d highly recommend dropping notes for the devs if you find other places to add them :slight_smile:


Based on what was said already and taking that into account, this is generally what I try to use it for:

  • Obvious typos
  • Cases where it marks casual wrong when it wants polite (and vice versa) and either form could be valid since remembering the grey text is a constant problem (but this is only most times, if the sentence clearly dictates what it should be then it’s my fault for not reading the sentence)
  • When I don’t know what type of word something is (almost exclusively -eru and -iru exceptions or na-adjectives that end in “i”), didn’t learn that word yet and it was the only mistake
1 Like