Learn Hardcore German: Die Katze greift vorsichtig nach dem Ball, den die Nachbarin wirft. - The cat carefully reaches for the ball that the female neighbor throws.

Because the preposition nach always takes the dative case. The verb phrase is nach etwas greifen (“to reach for something”), so you get nach dem Ball (dative masculine). Using accusative (den Ball) would suggest a direct object, which you don’t have with nach. If the cat actually grabs the ball, you’d typically use verbs like packen, fassen, or (er)greifen instead of plain greifen.

Why is the relative pronoun den and not dem?

Relative pronouns agree with their antecedent in gender and number, but their case is set by their role inside the relative clause. The antecedent is masculine singular (Ball), but inside the clause it’s the direct object of wirft, so you need the accusative: den. You can test it by making the clause a standalone sentence: Die Nachbarin wirft den Ball.

Why is wirft at the end of the relative clause?

In German subordinate clauses (including relative clauses), the finite verb goes to the end: ... den [Relativpronomen] die Nachbarin [Subjekt] wirft [Verb]. In the main clause, German is verb-second: Die Katze [1] greift [2] vorsichtig nach dem Ball [3…].

Do we need the comma before den?

Yes. German requires a comma before a relative clause: ..., den die Nachbarin wirft. Unlike English, both restrictive and non‑restrictive relative clauses are set off with a comma.

What nuance does greift nach have?

greifen nach means “to reach for,” implying an attempt or careful motion, not necessarily success. For actually grabbing, use packen, fassen, sich schnappen, or more formal ergreifen. Example: Die Katze greift nach dem Ball, but Die Katze packt den Ball.

Why doesn’t vorsichtig have an ending?

When adjectives are used adverbially, they are uninflected in German: Die Katze greift vorsichtig. When used attributively before a noun, they take endings: die vorsichtige Katze.

Can I move vorsichtig to another position?

Yes, within limits:

Neutral: Die Katze greift vorsichtig nach dem Ball.
Emphasis: Vorsichtig greift die Katze nach dem Ball.
Die Katze greift nach dem Ball vorsichtig is possible but sounds awkward. Keep manner adverbs like vorsichtig close to the verb. With other adverbs, follow the rough order Time–Manner–Place.

Could I use welchen instead of den?

Yes: ..., welchen die Nachbarin wirft. It’s grammatical but sounds more formal or bookish. den is the default in everyday German.

Is den here the same as English “that” in “the ball that ...”?

Functionally, yes—it’s the relative pronoun. German uses the article‑like set der/die/das (and their cases) as relative pronouns. Note:

Nominative: der (m), die (f), das (n), die (pl)
Accusative: den (m), die (f), das (n), die (pl)
Dative: dem (m/n), der (f), denen (pl) Don’t confuse das (neuter relative pronoun) with dass (the conjunction “that”).

What case is die Nachbarin here, and why not der Nachbarin?

die Nachbarin is nominative singular—the subject of wirft. der Nachbarin would be dative singular (e.g., “to/for the neighbor”). Also, Nachbarin (with -in) marks a female neighbor; the male form is der Nachbar.

How are werfen and greifen conjugated?

They’re strong (irregular) verbs:

werfen: ich werfe, du wirfst, er/sie/es wirft; Präteritum: warf; Partizip II: geworfen
greifen: ich greife, du greifst, er/sie/es greift; Präteritum: griff; Partizip II: gegriffen

Can I rephrase the relative clause with a participle?

Yes. Two common options:

Passive relative: ... nach dem Ball, der von der Nachbarin geworfen wird.
Attributive participle: ... nach dem von der Nachbarin geworfenen Ball. The participle version is compact but a bit more formal/literary.

Is nachdem the same as nach dem?

No. nach dem = preposition nach + article dem (“after/for the” in space/time), governs dative. nachdem (one word) is a conjunction meaning “after (doing/that),” introducing a clause: Nachdem die Nachbarin den Ball geworfen hatte, ...

How would things change with a different gender or plural?

The relative pronoun changes, and the dative after nach changes too:

Feminine: nach der Flasche, die die Nachbarin wirft
Neuter: nach dem Seil, das die Nachbarin wirft
Plural: nach den Bällen, die die Nachbarin wirft

Can I front the prepositional phrase?

Yes, for emphasis or topic shift: Nach dem Ball, den die Nachbarin wirft, greift die Katze vorsichtig. Keep verb‑second in the main clause and punctuate the fronted phrase (with its relative clause) with commas.

Could I replace die Nachbarin with sie in the relative clause?

Grammatically yes: ..., den sie wirft. But it can be ambiguous, because sie might refer to die Katze or die Nachbarin. Using die Nachbarin keeps the reference clear.