Translate: They need us to arrive before the beginning of the ceremony.

Question

I don't understand why arrivions was incorrect and soyons arrivés correct when:
The correct translation for "They need us to arrive before the ceremony begins" is "Ils ont besoin que nous arrivions avant le début de la cérémonie."
 
Explanation
Ils ont besoin que nous arrivions avant le début de la cérémonie
 
This phrase uses the subjunctive present (nous arrivions) of "arriver."
 
It expresses a requirement concerning a future action (our arriving) that must happen before a specific event (the ceremony starts).
 
This is the most natural and idiomatic way in French to say that someone needs you to arrive before a certain point in time.
 
Ils ont besoin que nous soyons arrivés avant le début de la cérémonie
 
This form uses the past subjunctive (nous soyons arrivés).
 
It emphasizes the state of having already arrived by the time the ceremony begins, which can sound overly formal, final, or focused on the end result.
 
In everyday French, this structure is less commonly used for planned requirements about the future.
 
Why?
French typically uses the present subjunctive ("nous arrivions") after verbs that express necessity or desire (like "avoir besoin que") unless you need to stress that the action will be completed before the reference point in the past or for a resultative state.
 
In the context of "They need us to arrive before the ceremony begins," the English meaning aligns exactly with the present subjunctive in French.
 
So, the most natural and correct answer is:
 
Ils ont besoin que nous arrivions avant le début de la cérémonie.
 
If your intent was, "They need us to have already arrived before the ceremony begins," you might use the past subjunctive, but that's not the usual reading of the English sentence.

Cécile Janty-Davies · Accepted Answer

Bonjour Robert,
Having consulted our English/French specialist, this is what they have said: 
"This is an unavoidable problem due to the differences between English and French. The English is correct; we use the present infinitive."
Our AI assistant says -
"Both sentences are grammatically correct in English, but they have slightly different meanings:
"They need us to arrive before the start of the show" - This is the more common and natural way to express this idea. It means they want us to get there before the show begins.
"They need us to have arrived before the start of the show." - This uses the perfect infinitive and emphasizes that our arrival should be completed before the show starts. It's slightly more formal and puts extra emphasis on the timing being crucial.
In most everyday situations,  you'd use the first version. The second version might be used when the timing is particularly critical or when you want to stress that the arrival must be fully accomplished before the show begins (not just that you should be in the process of arriving).
 
Both are correct, but "they need us to arrive before the start of the show" is more natural and commonly used."
 
We often receive comments like this when using tenses like 'le futur antérieur', which is rarely used in English, and can sound highfalutin.
As always, French is more rigorous, using 'la concordance des temps' very strictly.
Bonne Continuation !