Mitsuko Yoshida (asker) Dec 7, 2017:

Many thanks!!! Thank you Catharine Cellier-Smart, Sheila Wilson, Mark Nathan, and Port City. I really appreciate your comments.

Port City Dec 7, 2017:

It is better to state why you can't sell alcohol. I suggest you clearly state that it is prohibited to sell alcohol to minors. Besides the one suggested by Mark, you can use such expression as "It is illegal to sell alcohol to anyone under the age of 20."
Also, I often see something like "Please don't be offended if we ask for your ID if you look below 25." (in a jurisdiction where it is illegal to sell alcohol to people below 18).

Mitsuko Yoshida (asker) Dec 7, 2017:

Changed to: We cannot sell alcohol to anyone under the age of 20 and may ask for identification to confirm this.

Mitsuko Yoshida (asker) Dec 6, 2017:

There were no hits in Google for "The consumption of alcohol is illegal for minors. "
On the other hand, I could find 1200 hits for "It is illegal for minors to drink alcohol."

Mark Nathan Dec 6, 2017:

Oh dear That sentence is not very good either. "The consumption of alcohol is illegal for minors and people who intend to drive".

Mitsuko Yoshida (asker) Dec 6, 2017:

Sorry!!! We cannot sell liquorl to anyone for whom we cannot confirm that they are 20 years or older.

The above sentence is followed by "It is illegal for minors and those who will be driving to drink alcohol."

Sheila Wilson Dec 6, 2017:

Do any of those images show these exact words? I doubt it. @ Sue-my, sandwiching those words between "If" and "we reserve the right not to serve them." would be acceptable (though not exactly what I would expect to see). Not all native speakers are great writers, but professionals are paid to be good.

Catharine Cellier-Smart Dec 6, 2017:

@Sue-my Maybe one native speaker used "we cannot confirm that they are 20 years or older."
But I agree with my colleagues it doesn't sound natural. It would be better to say something along the lines of "Where there is doubt as to whether a person attempting to buy alcohol on these premises is aged 20 or over, it will not be sold to the person except on production of evidence showing the person to be 20 or over". That's the official wording used in Scotland for example, with a different age (use "liquor" instead of "alcohol" if necessary)

Mark Nathan Dec 6, 2017:

The sale of *** is prohibited by law to persons... https://www.google.fr/search?client=firefox-b-ab&dcr=0&biw=1...

Mitsuko Yoshida (asker) Dec 6, 2017:

A native speaker used "we cannot confirm that they are 20 years or older. "

Sheila Wilson Dec 6, 2017:

Nearly You do indeed see similar signs, Mark. But the words used here are just not right.

Mark Nathan Dec 6, 2017:

@Sheila Surely it is one of those signs you see in places that sell alcohol/liquor (but not to people under a certain age).

Sheila Wilson Dec 6, 2017:

I should worry more about the rest of the sentence Are these young people really selling rather than buying? It seems unlikely. And the last part of the sentence is very unnatural as we don't tend to use "age" in that way.

Mitsuko Yoshida (asker) Dec 6, 2017:

typo liquorl → liquor