I’ve seen those two quite different usages of that following an -of- prepositional phrase connecting two noun phrases and via the preposition of, one in which it is used to refer to the first noun phrase and other times to the second noun phrase, at least in some writings.
For example, it refers to the first noun in the -of- prepositional phrase here in sentence (1) because only is singular like the verb:
- [One] of them [that is red is running away] from here.
But in this second sentence, the that refers instead to the second element of the -of- prepositional phrase because it has a plural verb and so must refer to the plural , not to the singular :
- There’s one of [them that are unable to continue].
But now, apparently, the that in sentence (2) refers instead to the second noun phrase.
Which of the two distinct usages shown above is correct — or incorrect?
Personally, I consider the first usage to be the only correct one. If the second usage is wrong, what approach am I allowed to use to unambiguously refer to the second noun phrase?
In other words...
When the grammatical number of differs from that of so that just one is singular and the other plural, you can always tell which is intended provided that the verb is in the present tense or that it uses be (because was and were are distinct in the past tense just as is and are are distinct in the present tense).
But when both and have the same grammatical number, or when the verb is in the past tense and isn’t be, then unless they exists a rule telling you which is which, you cannot automatically and unerringly identify the antecedent of that.
What’s the rule we should use here, both as writer/speaker and reader/listener, to guarantee understanding of the intended antecedent?