He was the first person to be killed in the fire.
He was the first person killed in the fire?
Correct.there is a grammatical rule: when a noun is modified by words like the first , the second, if you have to choose a non-predicative verb(to do, doing ,and done, for example) to modify it, you have to choose infinitive(to do).
Both.However, I am confused when I tried to translate sentences above.Which is right?
I do not understand why you have problem with that rule.OR the rule just doesn't make any sense?
He was the first person [PRO to be killed in the fire].
"to be" is a predicative verb, a linking verb, a copula. In the bracketed non-finite clause above, it can be ellipted. Your rule refers to non-predicative verbs and the necessary resort to ellipsis, which do not concern us in the matter at hand. What is of issue here is the fact that, with a non-finite linking verb in the postmodifying adnominal clause, ellipsis is an option.