Could you tell me which is the correct form?
1.I first met Max one/a day last summer.(For me,it’s ‘one’)
2.I 'm so busy I only have one/a free day a week…(For me,it’s ‘one’)
3.I never know what I am going to be doing from a /one day to the next.(For me,it’s ‘one’)
4.I have to have a/one snack in the afternoon.(For me,it’s ‘a’)
5.One/a company refused to insure me, and a /one company said they would if I got a/one medical certificate.( one,one,a)
So a/one day day last week I went to see a /one doctor ant I had a/one checkup.I passed the examination and got a/one certificate.(For me it’s one,a,a)
I went from a/one company to another looking for the best price, but I didn’t find a/one quote under 300$.(For me it’s ‘one’ ,‘a’).

You are correct all the way through, though you missed the final ‘a’ from your 6th line. (one/a/a/a).
I presume ‘ant’ is a typo and you realise it is ‘and’.

I think a can be also acceptable in almost all cases.

I think a can also be acceptable in almost all cases.

Hi Bookaholic.

You cannot use ‘a’ correctly where ‘one’ is indicated as the correct answer in numbers 1 to 3 or in some of number 5.

Why a can’t be acceptable in the 5th sentence? I think all are not defined and don’t imply any number.

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