De, des, du, d'
Can somebody please give me a few ground rules so I can remember when to use these words. I am always mixing it up and just when I think I've got it I forget or I learn that you use them in another way in a sentence.
Sure sure, « du » is contraction of de + le (masc.) so it's used to mean about, some or 'of the (masc.)'. « je voudrais du thé » I'd like some tea. In this case it means some.
« de » is just of with no gender, so it goes usually everywhere. You have to use « de » with adjectives, even with plural ones -> « elle a de beaux yeux » not des.
« des » is plural, used like de but for plural. « A-t-il des chemises? » Does he have (any, some) shirts?
« d' » is only used for singular word beginning with a vowel regardless of gender. « je viens d'aller... » I just went... Its just shortened for de/du/de la for vowel harmony
This is not all but hope these ground rules help
Ps pro-tip; you have to use « de » after the 'some' constructions (quelque chose, quelqu'un) -> « C'est quelque chose de drôle » "It's a funny thing"
[French here, not linguist.] Not much to add to Langophobe's answer, but maybe an other point of view / other way of explaining, and a few confusing examples.
"de" is some kind of all-purpose word. It links two words together (I believe it will always be the words right before and right after... anyone see an exception?)
"Le chat de ma voisine" => "The (male) cat of my (female) neighbour" Often, "de/du/des/d' " can be translate by this "of", but it's not always the case.
In many cases, it indicates an unidentified/irrelevant/uncountable quantity, and will be translated in "some", like in Langophobe's examples : "Je voudrais du thé" => "I would like some tea" "Je voudrais un thé" => "I would like a (cup of) tea"
Some examples are trickier (I'll stick to the perfect example of pretty eyes)
"Elle a de beaux yeux",
"Elle a deux beaux yeux", and
"Elle a des beaux yeux"
are all absolutely correct. It will depend on what you want to put emphasis on.
They all basically mean "She has (2) pretty eyes", but you'll prefer the second in a very descriptive text (or very visual poem, etc.), and I feel like [told ya, not linguist] the third would insist a bit much on the fact that each of her eyes is beautiful. Oddly enough, putting "de" in plural ("des") stresses the number of eyes.
A bit like asking "On voudrait des thés" => "We'd like some teas" instead of "du". The waiter is expecting a different tea for each person. That's already more information that the generic du.
In cases where it doesn't involved neither possession/relation ("Le chat de la voisine", "Thor, fils d'Odin", etc.) nor a quantity thing, it can often be after verbs :
"Je reviens du boulot" => "I'm back from work"
"Je viens de finir" => "I just finished" (de simply serves as a link between coming (venir) and finishing (finir), you could see it like "coming from finishing (a task)" is "just finished (the task)" )
"vivre d'amour et d'eau fraîche" => "To live on love and fresh water" (i.e. All you need is love)
"avoir besoin de quelquechose" => "to need [...] something"
or replacing many different english preposition
next to => proche de
in front of => en face de
he is from => il est de
red with anger => rouge de colère
in what/this way => de quelle/cette façon
stone [...] house => maison de pierre (yes, even nothing can turn in de)
or introducing a verb, like "Je viens de finir :
arrêter de courir => to stop running
dis lui "arrête !", but dis lui de s'arrêter (tell him "stop!", tell him to stop)
So really, "de" is all purpose. I'm sorry, but you'll find it meaning various things. But the main ones are : "of" and "unspecified/irrelavant/uncountable quantity of", and anytime you want to put a link between two words...
If you can be more specific on the exemples on which you struggle, I can probably be of more help ! (d'une plus grande aide)