"The little boys have kept quiet for an hour."
Translation:Les petits garçons se sont tus depuis une heure.
"Pendand" may be used in "Ils sont restés silencieux pendant une heure" or "Ils ont restés en silence pendant une heure" or maybe "Ils ont gardé le silence pendant une heure". In all these sentences we used "static verbs" (I'm not sure about the linguistic terminology). But In the given sentence, the verb "se taire" is required, which is more of an action verb.
It is like "To remain/keep quiet for a certain period of time" vs "To shut up since a given moment" or "To keep shut up since that particular moment". The verb "se taire" is more emphasising the act of engaging to not make noise rather than the state of being quiet so it must happen at a particular moment in time and keep the engagement unbroken "since" (for) a period. That's why "depuis" is more relevant with this verb than "pendant".
Lulularosa, I think what you're referring to is a phrase like "I have been living in New York for 5 years."-> An ongoing action that started in the past, but is still continuing now, and that you could translate with: J'habite à New York depuis 5 ans."
But in English, this can only happen in a sentence where there is an -ing-verb. And then you have two options:
1) A sentence that describes a situation that is still going on today: I have been living in Hamburg for 7 years, Je vis à Hamburg depuis 7 ans. The three boys have been keeping quiet for an hour --> Les garçons se taisent depuis une heure.
2) A sentence that describes a situation that is already going on when an action happened: "The three boys were keeping quiet, when he entered the room." Here you would use the imparfait to describe the situation and the passé composé for the action -->Les garçons se taisaient (situation) quand il est entré dans la pièce (action).
Another option is a sentence in English where a specific date is mentioned: "The three boys kept quiet for an hour yesterday". Then you would use the imparfait in French --> Les trois garçons se taisaient pendant une heure hier.
But this Duolingo sentence, "The little boys have kept quiet for an hour" the situation that lasted for an hour is already over when the speaker tells of the situation. So in this case it is: " Les trois garçons se sont tus pendant une heure.
Thanks for this clear and detailed explanation. I had completely missed the significance of the use of the present participle on the english side of the equation. (at this point, feel free to insert a loud "Duh!"). Have a lingot!
Only, in the given sentence, the action may not be over, that would be "The little boys kept quiet...".
And now that I think about it "I have known you a long time" (without an '-ing verb' = "Je te connais depuis....".
Any further thoughts?
A month after my last comment I am still unclear about the match between the given English and French sentences: "The little boys have kept quiet for an hour" and "Les petits garçons se sont tus depuis une heure."
From what we have learned, it seems to me :
1) If the meaning is "the boys kept quiet for an hour and now they are yelling and screaming", the French should be "Les petits garçons se sont tus pendant une heure";
2) if the meaning is "the boys have been quiet for an hour (or, since one o'clock?) and are still quiet", the French should be "Les petits garçon se taisent depuis une heure".
But in Duolingo the original phrase is always the French one, and this one is written with passé composé + depuis and translated into the present perfect, which seems to be incorrect.
I know how tenuous my grasp of French grammar is and also how easy it is to follow partially understood rules too rigidly. So, could one of our experts please correct the faults in my reasoning.
It's not a correct translation. The present perfect here must be a "Présent de l'indicatif" in French. The correct translation shoud be : Les petits garçons se taisent depuis une heure. The action (keep quiet) started one hour ago and it's still true when I say the sentence : that's why we use a present perfect in English and it MUST be a "Présent de l'indicatif" in French