"El cădea rar."

Translation: He used to fall rarely.

[Mike484370]

"He used to rarely fall" would be more natural sounding

[Joemaza]

Alt Eng: He would rarely fall.

[BenYoung84]

Yeah I don't know about all of your "would" translations. "would" can have a past habitual meaning sometimes but only in certain contexts. In isolation I fear the danger of muddying it with the conditional is great.

[Joemaza]

I think your key word here is context and pragmatics. Verbal forms may not have one single translation. By your comment of "muddying" it with the conditional is similar to saying the past progressive translations muddy past tense translations as they, too, would fit here in "certain contexts".

I see what is trying to be taught and it might be used often in Romanian. But, to my ear, a translation with "used to" and "rarely" is dissonant. And, I would wager that if you were to survey corpora, you would not likely find them together in the same clause.

[JojoKos]

You would never say "He used to fall rarely" in English. We say, "He rarely fell".

[Pop60]

"He seldom used to fall" was my answer but from other suggestions "He fell rarely" looks far and away the most natural English.

[Deisi92]

Și ar putea însemna „slowly” ca în „a vorbi rar”?

[EdgarasUko]

This sentence doesn't make sense, like it happened many times but actually it didn't....

[JohnGardne7]

Or perhaps he falls more frequently now.

[RichBaker10]

In English it should be "he used to rarely fall"

[BenYoung84]

I would say that "He rarely used to fall" works much better.

[Ray301962]

"To rarely fall" is a split infinitive. Do they still teach that as a no-no?

[JohnGardne7]

Not really. But it's not normally encouraged, either. Indeed, there's no need for an infinitive here. "He rarely fell" can hardly be a preterite verb--if you're talking about rarely or frequently you are obviously discussing continuing pattern over a period of time.