A/an with adjectives modify plural nouns

[diplomacy]

I have read that indefinite articles can be with adjectives that modify plural nouns.
Ex:
When he was a teacher,he has an embarrassing things.

I bought a new cars.

Could you please tell me the correct grammar.

 

[5jj]

When he was a teacher,he has [STRIKE]an embarrassing things[/STRIKE].

I bought [STRIKE]a new cars[/STRIKE].

These are incorrect.

 

[diplomacy]

Do indefinite articles come with plural nouns even if there are exceptions?
Could you please clear it straight?
It confused me too much.

 

[Barb_D]

Don't use "a" or "an" with plural nouns. Period.

You can say "some" or "a few" or "many" (as well as other words) but not "a/an."