Learn Hardcore Dutch: Zij past af en toe op haar nichtje en vindt dat leuk. - She babysits her niece now and then and likes it.

Here you have the construction (op) iemand/iets passen = “to look after, to mind.” So Zij past … op haar nichtje means “She looks after her niece.”

When you talk about babysitting in general (without naming the child), Dutch also uses oppassen: Ik ga vanavond oppassen.
When you name the person, Dutch very often uses (op) iemand passen: Ze past op de kinderen.
Note that oppassen also means “to be careful” (Pas op! = “Watch out!”), so context matters.

Both patterns exist; with an explicit person, (op) iemand passen is very common and completely natural.

Why is it past and not pas?

Present-tense conjugation of passen (in this use “to mind/guard”):

ik pas
jij/je past
hij/zij/ze/het past
wij/jullie/zij passen

Because the subject is zij (she), you get zij past.

Can an adverb like af en toe really go between past and op haar nichtje?

Yes. Af en toe (“now and then”) is a time adverbial. It’s perfectly normal to place a time adverb between the finite verb and the prepositional object:

Zij past af en toe op haar nichtje.

Is af en toe the same as soms?

Close, but not identical:

af en toe = “once in a while/now and then” (feels a bit less frequent or more occasional)
soms = “sometimes” (neutral, could be more frequent)

Other near-synonyms: nu en dan, zo nu en dan, weleens/wel eens (context-dependent).

Why is it Zij and not Ze?

Both mean “she.” Zij is the stressed form and can add emphasis or contrast (“she, as opposed to someone else”). Ze is the unstressed, everyday form. In casual speech you’ll most often hear Ze: Ze past af en toe op haar nichtje …

What exactly does nichtje mean—niece or cousin?

In Dutch, nicht means both “niece” and “female cousin.” The diminutive -je gives nichtje, which often implies a younger person and is very commonly used for a niece. The male counterpart is neef / neefje (nephew or male cousin). Context usually makes clear which family relation is meant.

What does the diminutive -je in nichtje add?

It often signals the person is a child or is viewed affectionately.
With family terms it’s very common: dochtertje, zoontje, neefje, nichtje.
You can still say nichtje for an adult niece; it doesn’t necessarily mean “tiny,” just a younger-generation relationship or a warm tone. (Note: nicht without -je is more likely to be read as “female cousin.”)

Does haar necessarily refer to the subject here?

Not necessarily. Haar means “her” (possessive), and it refers to some female person that’s clear from the wider context. In this sentence it most naturally refers back to the subject, but grammatically it could refer to another woman previously mentioned. If the possessor were male, you’d use zijn (“his”): Jan past op zijn nichtje.

Why is vindt spelled with -dt?

The infinitive is vinden (“to find; to think”). The stem is vind-. In the present tense you add -t for third person singular:

ik vind
jij/je vindt
hij/zij/ze/het vindt

So the spelling is vindt (stem ending in d + t). It’s pronounced like a final t.

What does the structure vindt dat leuk look like under the hood? Could I say vindt leuk dat?

The pattern is: [Subject] vindt [Object] [Adjective].

Zij (subject) vindt (verb) dat (object pronoun referring to the activity) leuk (adjective = “fun/pleasant”).

The order vindt leuk dat is not idiomatic. Keep the object before leuk: vindt dat leuk.

Can I use het instead of dat: Zij vindt het leuk?

Yes. Both het and dat are possible.

Zij vindt het leuk = “She likes it” (neutral, “it” in general).
Zij vindt dat leuk = “She likes that,” with dat pointing back more explicitly to the specific activity mentioned earlier. Using dat often feels slightly more specific/emphatic.

Why is the second zij omitted after en?

In coordinated clauses, if the subject is the same, Dutch commonly leaves it out to avoid repetition:

Zij past … en (zij) vindt … → Zij past … en vindt … It’s not wrong to repeat zij, but it’s heavier and less natural here.

How do I turn this into a question?

Use inversion (finite verb before the subject):

Yes/no: Past zij af en toe op haar nichtje? Vindt zij dat leuk?
Wh-:
- Hoe vaak past zij op haar nichtje? (How often…)
- Op wie past zij? (Who does she look after?)

What happens in a subordinate clause (e.g., with omdat)?

In a subordinate clause, the finite verb goes to the end:

Main: Zij past af en toe op haar nichtje en vindt dat leuk.
Subordinate: … omdat zij af en toe op haar nichtje past en dat leuk vindt.

What’s the difference between leuk vinden, graag doen, and houden van?

leuk vinden
- object/activity = to think something is nice/fun/pleasant. Neutral “like.”
  - Zij vindt oppassen leuk.
graag
- verb = to like doing something.
  - Zij past graag op. (She likes to babysit.)
houden van
- person/thing = to love (or like very much), stronger; typically for people, animals, music, food, etc.
  - Zij houdt van kinderen.

Do I need a comma before en here?

No. Dutch normally doesn’t use a comma before en when joining two short, closely related main-clause parts with the same subject. A comma can appear for clarity in longer sentences or when clauses are heavier, but it isn’t needed here.

Any quick pronunciation tips for tricky words like Zij, vindt, nichtje, and leuk?

Zij: the ij is one sound, roughly like English “ay” in “day,” but a bit tenser.
vindt: the final -dt sounds like a plain t.
nichtje: the ch is a throaty sound (like Scottish “loch”), and -tje sounds like “-tyuh.”
leuk: the eu is a rounded vowel, roughly like the vowel in French “deux.”

Could I replace the first half with oppassen or babysitten?

Yes, but mind usage:

Very common: Zij past af en toe op (haar nichtje).
General activity: Zij gaat af en toe oppassen. (no direct object named)
Borrowed verb: Zij babysit af en toe. / Zij gaat af en toe babysitten. This is widely understood; in the Netherlands many speakers still prefer (op iemand) passen/oppassen, while in Belgium babysitten is extremely common. If you name the person, (op) iemand passen is a safe, natural choice: Ze past af en toe op haar nichtje.