until

Hello

Until you do that, you will be told that you do not have permission to post.  I'm sure that the first part of this sentence says (If you don't do that..) I'm just wondering because the word "until" has usually a negative meaning when used after the negative verb, e.g. They did not come until the meeting was half over, however, in this case "until" is before a negative verb. I'm not sure if you understand what I mean

Until you have activated your account, you will not be able to post messages. I conclude that the first part of the sentence says that "if you don't activate your account.." I think this is a similar situation to what I wrote above. Can't I just write it: Until you don't activate your account..

thanks 

  "UNTIL version says: "You will not be  able  to  post  messages
  before you activate your account", or "You  will  be  able  to
  post only after you activate your account"."

  To avoid any confusion, those sentences can be rewritten using
  Present Perfect:

  1) "...  before you have activated your account"
  2) "... only after  you have activated your account"

Newguest

Can't I just write it: Until you don't activate your account.

The pattern you show here is quite common.  It's similar to the same clause with unless instead of until.  The unless clauses are like if ... not clauses.  But the until clauses have a temporal component (not present in the unless clauses) which conveys the idea that the negative consequence lasts only as long as the positive condition lasts.  That is, when the condition reverses, as it is expected to do in the course of time, the consequence does as well.

Thus,

Unless you ask, you won't know the answer.

says If you don't ask, you won't know the answer.  The passage of time is not involved.

But

Until you ask, you won't know the answer.

says that as long as you continue not to ask, you will not know the answer, and implies that the asking must be done before knowing the answer can occur.  A possible paraphrase is You have to ask before you can know the answer.

Here are a few examples.  They are modified versions of sentences I found on the Web.

Unless you take the medicine, you will not feel better. [If you don't take the medicine, you will not feel better.]

Unless you try, you won't know whether you can do it. [If you don't try, you won't know whether you can do it.]

Until you try, you won't know whether you can do it.  [You have to try before you know whether you can do it.]

I'll leave the rest for you to think about.

[Unless / Until] you retire, you will not be eligible for membership.

[Unless / Until] you provide evidence, you will not be taken seriously.

[Unless / Until] you are registered, you will not be able to access the site.

[Unless / Until] you master the language, you will not have much academic success.

[Unless / Until] you delegate responsibilities, you won't enjoy the freedom of being a business owner.

CJ

As for Ant's reply, I understand that the sentence: Until you have activated  you account, you will not be able to post messages; means the same as: You will not be able to post messages before you have activated your account.

This sentence above is quite different from all the other examples you gave me Calif.

Your sentences were usually: Until you ask you.. without the present perfect tense. Nevertheless, I think I understand it.

take care

Newguest

How's that?

CJ