Vieux = old Ancien = ancient / antique. In the case of the car, both are old yes. But the "ancienne voiture" means specifically that this car is from the 70's,60's or older... It's a nice car that was released many many decades ago. The "vieille voiture" can also refer to the release year, but it kind of implies that the car is a piece of crap or at least it has been quite used. For neuf/nouveau, let's say you buy a phone. The phone is new (neuf), you just bought it. But since you replace your old phone, it's also your new phone (nouveau téléphone). You would say to your friend "regarde mon nouveau téléphone" (look at my new phone) but you would never use "neuf" in this case. Neuf is when you're talking about a specific product that was just purchased. You can use nouveau to speak about a trend, a phone model, etc. I'm not sure if it's clear... It may be difficult to grasp but it's harder to explain :)

Thank you everyone for your input. Peachey you're appealing to the music nerd inside me, thanks a lot for the (late) discovery. Su.Ki you are totally right regarding US media. I started learning English quite young playing videogames that weren't translated, trying to understand lyrics in music or later getting interested in only original versions of tv shows or movies. I've heard both pronounciations within the same tv show so I was curious about it ;)

J'ai de la peine à trouver un exemple, mais cela veut dire que tu joins ce qui est "utile / productif" avec ce qui est "agréable / appréciable". Imaginons que tu dois aller à Las Vegas pour le travail (utile) et que tu décides lors de ta soirée de congé d'aller parier, jouer aux machines à sous, etc. (agréable). Tu as su tirer le meilleur parti d'une situation ennuyeuse / monotone en saisissant une opportunité. Je ne sais pas si je suis très clair, j'espère que j'ai répondu à ta question.

Do you have any context to provide for your first quotes? "Relever" can have several meanings. You can "relever" a dish by spicing it up. Another meaning would be something like "to pick up", but it has a specific context. Fo instance you would "relever" the fingerprints of a felon at the police station. Another meaning I see is something like "to notice" but the context would be for small details. For instance, if you set up a prank but there are obvious clues around, you hope your mate won't "relever" those details.

De temps en temps, quand il y a des catastrophes, on poeut voir les organismes humanitaires prendre les mesures necessaires pour venir en aide aux victimes. Cependant, ces organismes sont souvent intriqués avec la politique et aident à couvrir les échecs du gouvernement, ce qui peut soulever la question suivante: l’aide humanitaire est-elle réellement efficace ou s’inscrit elle necessairement dans une logique d' "apparence" ? For the last part, I'm not sure I understood you correctly. If you meant that those organizations are there just to make things pretty and give a good image of the governments instead of realy being there to help people. I would say "...l’aide humanitaire est-elle réellement efficace ou s’inscrit elle necessairement dans une logique supericielle?"