Μου αρέσει η ποικιλία στα φρούτα, αλλά συνήθως αγοράζω μόνο όσα χρειάζομαι για δύο μέρες.

Because αρέσει works differently from English like.

Literally, μου αρέσει is closer to it is pleasing to me:

• μου = to me
• αρέσει = pleases

So in this sentence:

• η ποικιλία is the thing that is pleasing
• μου is the person who likes it

That is why Greek uses:

• Μου αρέσει η ποικιλία = I like variety

This pattern is very common:

• Μου αρέσει ο καφές = I like coffee
• Μου αρέσουν οι ταινίες = I like movies

Notice that the verb changes depending on what is liked, not on the person doing the liking.

Because the subject of the verb is η ποικιλία, which is singular.

• η ποικιλία = the variety
• so the verb is singular: αρέσει

Even though φρούτα is plural, it is not the subject here. It is part of the phrase στα φρούτα.

Compare:

• Μου αρέσει η ποικιλία στα φρούτα. = I like the variety in fruit.
• Μου αρέσουν τα φρούτα. = I like fruit.

In the second sentence, τα φρούτα is the subject, so the verb is plural: αρέσουν.

Μου is the weak form of εμένα / σε μένα? Actually for the first person it means to me or sometimes my, depending on context.

Here it is the indirect object:

• μου αρέσει = it pleases me / I like

So μου is in the genitive form, but in this kind of sentence it functions like to me.

Other examples:

• Σου αρέσει; = Do you like it?
• Του αρέσει η μουσική. = He likes music.
• Μας αρέσει το καλοκαίρι. = We like summer.

Στα is a contraction of σε + τα.

• σε = in, at, on, to
• τα = the
• στα = in the / among the / with the

So:

• στα φρούτα literally = in the fruits
• more naturally here = in fruit or among fruits

Greek very often combines σε with the article:

• σε + το = στο
• σε + τη(ν) = στη(ν)
• σε + τα = στα
• σε + τους = στους

In this sentence, στα φρούτα means something like when it comes to fruit or among fruit choices.

Greek uses the definite article much more often than English.

So η ποικιλία literally means the variety, but in natural English we often just say variety.

This is very normal in Greek:

• Μου αρέσει η μουσική. = I like music.
• Αγαπώ τη φύση. = I love nature.
• Η υπομονή είναι σημαντική. = Patience is important.

So you should not always translate the article word-for-word.

Όσα means as many things as, whatever things that, or more naturally here, what / the things that.

In this sentence:

• αγοράζω μόνο όσα χρειάζομαι = I buy only what I need = more literally, I buy only as many things as I need

It refers back to an implied noun, which here is φρούτα.

So the full idea is:

• αγοράζω μόνο όσα φρούτα χρειάζομαι = I buy only as much fruit / as many fruits as I need

Greek often leaves the noun out when it is obvious.

Because it agrees with the implied noun φρούτα.

• φρούτο = fruit, neuter singular
• φρούτα = fruits / fruit, neuter plural

So the matching form is όσα, which is neuter plural.

Very roughly:

• όσος = masculine
• όση = feminine
• όσο = neuter singular
• όσα = neuter plural

Since the hidden noun is φρούτα, Greek uses όσα.

Because Greek often omits a noun when it is easy to understand from context.

Here, after mentioning φρούτα earlier, the speaker does not need to repeat it:

• μόνο όσα χρειάζομαι = only what I need

The full version would be:

• μόνο όσα φρούτα χρειάζομαι

But that sounds more explicit than necessary. The shorter version is natural and common.

English does this too sometimes:

• Take what you need instead of
• Take the things that you need

Good question. Χρειάζομαι is one of those Greek verbs that has passive/middle-style endings but an active meaning.

So:

• χρειάζομαι = I need

Its forms look like passive forms, but you translate it actively:

• χρειάζομαι χρόνο = I need time
• χρειάζεσαι βοήθεια; = Do you need help?
• χρειαζόμαστε χρήματα = We need money

So in the sentence:

• όσα χρειάζομαι = what I need

Do not try to translate it as am needed here.

Because Greek usually leaves subject pronouns out when the verb ending already shows who the subject is.

• αγοράζω already means I buy
• so εγώ αγοράζω is usually unnecessary

Greek verb endings often make the subject clear:

• αγοράζω = I buy
• αγοράζεις = you buy
• αγοράζει = he/she/it buys

You can add εγώ for emphasis or contrast:

• Εγώ αγοράζω μόνο όσα χρειάζομαι, όχι περισσότερα. = I buy only what I need, not more.

Μόνο means only.

It limits what the speaker buys:

• αγοράζω μόνο όσα χρειάζομαι = I buy only what I need

Without μόνο, the sentence would simply say:

• αγοράζω όσα χρειάζομαι = I buy what I need

With μόνο, the idea becomes stronger:

• just that, and no more

Συνήθως means usually.

Here it comes before the verb:

• αλλά συνήθως αγοράζω... = but I usually buy...

That position is very natural, but adverbs in Greek can often move around:

• Συνήθως αγοράζω μόνο όσα χρειάζομαι.
• Αγοράζω συνήθως μόνο όσα χρειάζομαι.

The first version is the most straightforward.

Because για can express duration: for.

So:

• για δύο μέρες = for two days

This means the speaker buys enough fruit to cover a two-day period.

Examples:

• Φεύγω για δύο εβδομάδες. = I’m leaving for two weeks.
• Έμεινα εκεί για μία ώρα. = I stayed there for one hour.

So here:

• αγοράζω μόνο όσα χρειάζομαι για δύο μέρες = I buy only what I need for two days

Because after για meaning for, Greek uses the accusative.

So:

• δύο μέρες is the accusative plural form

In this noun, nominative plural and accusative plural look the same:

• οι μέρες = the days
• (για) δύο μέρες = for two days

So even though the form looks simple, grammatically it is the accusative after για.

Yes.

• ημέρες is the more formal/full form
• μέρες is the common everyday form

So both are correct:

• για δύο μέρες
• για δύο ημέρες

In normal conversation, μέρες is very natural.

Αλλά means but and introduces a contrast.

The contrast is:

• I like variety in fruit vs.
• I usually buy only what I need for two days

So the speaker is saying: Even though I enjoy variety, in practice I buy a limited amount.

This is a very common use of αλλά.

It is not completely fixed, but it is a very natural phrase.

It means:

• variety in fruit
• variety among fruits
• a range of fruit choices

Greek often uses σε / στα after nouns like this to show the area in which the variety exists:

• ποικιλία στα λαχανικά = variety in vegetables
• ποικιλία στα χρώματα = variety in colors

So η ποικιλία στα φρούτα is a natural way to say that there are many kinds of fruit and that the speaker likes that variety.