'admit + noun' vs 'admit to + noun'

[Phoo]

What is the difference b/w the two below?

a. admit to the affair
b. admit the affair

Thanks!

[Phoo]

One more thing,

"Heads up! " even when you are telling one person, should you say "heads" instead of "the head"?

[Haihao]

[Yankee]

Hi Phoo

I would understand the same thing in your first two sentences: acknowledge/confess

"Heads up!" is a fixed expression and should not be changed to "Head up!"
"Heads up!" is a warning to a person or people about the existence of a potentially hazardous situation.

On the other hand, "Head up!" simply sounds like a literal command telling a person to raise his/her head.

[Mister Micawber]

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[Phoo]

Thank you all

I also see the exparession "a heads-up" sometimes and always wondering.
It is a fixed expression!! OK I've got it! It's like "heads or tails", isn't it?

[Mister Micawber]

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They are both fixed expressions, but 'heads or tails' refers to the obverse and reverse of a coin. 'A heads-up' (and the other permutations we have been discussing) refers to a real head-- it warns the listener, as Yankee has already told us, and in the original, urges the listener to raise his/her head and look about for trouble.
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Native English teacher at Mister Micawber's