The phrase "acknowledge at once" is correct and usable in written English.
It can be used when you want to emphasize the need for immediate recognition or response to something.
Example: "Please acknowledge at once that you have received the document to ensure we are on the same page."
Alternatives: "acknowledge immediately" or "recognize right away".
But, as he acknowledges at once, the task he has set himself for this book requires him to have what he calls "a theory or conception of racism".
But acknowledging all at once what amount of money will be necessary to recapitalise the banking system is sure to destroy public confidence (hencing the creeping bail-out).
This fuels suspicion that Iran really wants a bomb, or the capacity to build one at speed.Iranian officials acknowledge that, once the techniques for making uranium and plutonium are fully mastered, the only difference between a civilian nuclear programme and a military one is intent.
Even in Washington, officials acknowledge that once American forces depart, the Taliban likely will gain ground, at least in rural areas.
And I will acknowledge saudades once more.
But how can anyone, however gifted, devise a plan that will at once acknowledge the worst attack in our country's history, rebuild 10 million square feet of office space for which there is no discernible market and renew Lower Manhattan?
It may well be that what our society also requires is some kind of slow news, a manner of reporting present events that will at once acknowledge the novel situation, and also redress the balance between the ancient history before the web and a monstrous - and babyish - present.
So innovative were the stagings of Wieland Wagner that they seemed effortlessly to at once acknowledge and transcend the past and its controversies.
Again, the problem was acknowledged at Nice.
It was a paragraph which at once acknowledged that writers would lose out and demonstrated how little it understood or cared about Australia's cultural situation.
