- a. A beaver builds dams.
b. *One beaver builds dams.
- a. *A boy is tall.
b. One boy is tall.
- a. ?A boy is a son.
b. ?*One boy is a son.
3 is a non-sentence and b is a correct sentence?
Since 1 is the definition sentence after the subject, the indefinite article was used at the beginning of the sentence, and one became non-sentence.
On the other hand, 2 is not the case because all the boys are tall, so I think it will be reversed.
Is 3 in the same way as 1 in the case where 3 is a definition sentence?