"His pants are falling down."
Translation:Il perd son pantalon.
"son pantalon est tombé" (= his pants have fallen down/fell down) means that the pants are already on the floor. It is passé composé.
"his pants are falling down" is continuous present tense (that does not exist in French), to be translated to : "son pantalon tombe" or "son pantalon est en train de tomber".
I agree that this is fairly idiomatic and can be confusing for non-native speakers. 'Losing' something can also mean that the thing in question is slipping away or diminishing, often despite one's best attempts to prevent it from doing so. "I'm losing control", "I've lost my grip", "They're losing their lead", "We're losing the patient", and so on. So here, the phrase "He's losing his pants" does indeed mean that his pants are falling down, but it also suggests that the pants may be falling down despite the wearer's efforts to keep them up.
In this scenario in the present tense, "losing my/your/his/her pants" would refer to the act of the pants falling down right now. It would be like if someone wore pants that were too big for them and they were sliding off, you could say "look, he is losing his pants!" Or "Look, his pants are falling down!" And it would mean the same thing.
"Ses pantalons tombent" means that his multiple pairs of pants are falling down, but the English sentence almost certainly refers to the one pair of pants that he is wearing, which is "son pantalon" in French. I think "Ses pantalons tombent" could be correct if you're referring to a stack of pants on top of a dresser though.
How would I say "His pants" exactly? In French, I know you can't do possessives this way, so I assume it would be something like "The pants of he" (as uncomfortable as that would be in English). So, grammatically, how would French speakers make a possessive with a pronoun?
This sentence (i.e. "Ses pantalons tombent.") means that his multiple pairs of pants are falling down and that is not what the required answer is (The sentence provided by duolingo says that only one pair of pants are falling down.). Coming to "Ses pantalons tombent", "sont" is not necessary (in fact, not allowed in correct French)because "tombent" itself means "are falling/fall". That kind of an expression (probably?) doesn't exist in French.
French does not have a distinct verb form for present progressive. The present-tense form ‘perd’ is used both for present progressive “is losing” and the simple present “loses” — including the punctual present, generic present, and narrative present. If you want to emphasize the progressive nature of the action, use the paraphrase ‘en train de’, as in ‘Il est en train de perdre son pantalon.’ = “He's in the process of losing his pants.”.
I'm struggling quite a bit because I'm getting a lot of these that i haven't seen before and that are either without the translation drop downs or when they are there then the means to get the answer aren't for example when i learned 'On ne qu'une fois(still not 100% sure that is right?) I only got it through trial and error because it wasn't shown at all in any part of the translations, just a minor thing but it can get a bit annoying
Trial and error is at the core of Duo's teaching method. Reading sentence discussions helps to get the grammar and syntax. You can ask precise questions here and you will get answers. Once you have perfectly understood how to get the answer, they you should redo the lesson, and several times, so that what you have understood actually prints into your mind.
I have had it with this site, in the dictionary "perdu" is lost, fall down is "tomber" all I want to do is get by in France, however it seems to me that you have to second guess most things on here, also there are so many instances on Tu, Ta and so on but you have to know some one very well before you can use the informal so the main thrust should be to use the formal "vous" and so on, however most sentences now seem to use the informal but I have yet to come across one instance on the use of "on" which is not informal as such but is widely used instead of "nous", it seems a lot of effort is wasted here in trying to be somehow grammatically perfect and not to actually be able to converse in French to the level that you can make yourself understood.