a person vs. one person

[sb70012]

1. Luckily, only a person was injured. = (incorrect)
2. Luckily, only one person was injured. = (correct)

Source: ABC of Common Grammatical Errors by
Nigel D Turton. Part 3 , a/an Use

Hello teachers,

As you know when we need to emphasize “how many”, we can use one. See:
Luckily, only one saucer was broken. (not two, three, etc) = Correct
Luckily, only a saucer was broken. (not a cup, plate, etc) = Correct
If so, then why number 1 is incorrect? If (a saucer) is correct then why (a person) doesn’t fit in number 1?


Many thanks in advance.

***************************************

One English told me:

Your book is wrong because:

'Luckily, only a person was injured in the accident (no animals were harmed).' = can be correct too


But what's your opinion?

Thank you.​

 

[Rover_KE]

Before replying to this, Using English teachers, please read this first. Only partial context has been given here.

I did not say the book was wrong, and sb knows that.

Rover

 

[MikeNewYork]

1. Luckily, only a person was injured. = (incorrect)
2. Luckily, only one person was injured. = (correct)

Source: ABC of Common Grammatical Errors by
Nigel D Turton. Part 3 , a/an Use

Hello teachers,

As you know when we need to emphasize “how many”, we can use one. See:
Luckily, only one saucer was broken. (not two, three, etc) = Correct
Luckily, only a saucer was broken. (not a cup, plate, etc) = Correct
If so, then why number 1 is incorrect? If (a saucer) is correct then why (a person) doesn’t fit in number 1?


Many thanks in advance.

***************************************

One English told me:

Your book is wrong because:

'Luckily, only a person was injured in the accident (no animals were harmed).' = can be correct too


But what's your opinion?

Thank you.​

There was nothing at all wrong with Rover's explanation of the grammar. The difficulty with your first sentence is that we really wouldn't consider an injury to a person (as opposed to an animal, a tree, etc) to be lucky. If you change the species, it works just fine.

There was an accident on the highway. The car was totaled, but luckily only a deer was injured.