Learn Hardcore German: Wir entscheiden spontan, ob wir in die Innenstadt fahren. - We decide spontaneously whether we will go to the city center.

ob = whether/if (yes–no decision or indirect question). Use it after verbs like entscheiden, wissen, fragen.
wenn/falls = if/when (condition).
Examples: Ich weiß nicht, ob er kommt. vs. Wenn/Falls er kommt, gehen wir.

Why is the verb at the end in ob wir in die Innenstadt fahren?

Because ob introduces a subordinate clause; in subordinate clauses the verb goes to the end: ob + subject + … + verb.

Why is there a comma before ob?

German requires a comma before every subordinate clause. ob wir in die Innenstadt fahren is a subordinate clause, so you need the comma.

Why is it in die Innenstadt and not in der Innenstadt?

in is a two‑way preposition.

Movement into a place → accusative: in die Innenstadt (to downtown).
Location/state → dative: in der Innenstadt (in downtown).

What case is the die in in die Innenstadt, and why?

Accusative feminine singular. Innenstadt is feminine (die Innenstadt), and with in + movement you use the accusative, which for feminine is also die (dative would be der: in der Innenstadt).

Could I also say zur Innenstadt instead of in die Innenstadt?

Yes.

in die Innenstadt emphasizes going into and being inside the center.
zur Innenstadt (zu + der) emphasizes heading to or arriving at the area. Both are common; if you plan to spend time downtown, in die is usually the idiomatic choice.

Can I contract in die like ins (in + das)?

No. ins = in + das, im = in + dem. There’s no contraction for in + die; you must say in die.

Why use fahren and not gehen? Does fahren mean “to drive”?

fahren = go by vehicle (car, bus, train, bike, etc.). It can mean either to drive or to ride; context tells. If you mean you are the driver, say selbst fahren or Auto fahren.
gehen = go on foot.
So in die Innenstadt fahren implies going by transport, not walking.

Is Wir entscheiden uns spontan, ob … correct?

Avoid that. Standard is non‑reflexive with an ob‑clause: Wir entscheiden spontan, ob …
Use reflexive sich entscheiden with für/gegen or a zu‑infinitive:

Wir entscheiden uns spontan für die Fahrt in die Innenstadt.
Wir entscheiden uns spontan, in die Innenstadt zu fahren.

Can I say Wir werden spontan entscheiden, ob … to talk about the future?

Yes. German often uses the present for near‑future (Wir entscheiden …), but Wir werden spontan entscheiden … is fine and stresses the future act of deciding.

Where can I put spontan? Does position change the meaning?

Wir entscheiden spontan, ob … = the deciding is spontaneous.
Spontan entscheiden wir, ob … = same meaning, with emphasis.
Wir entscheiden, ob wir spontan in die Innenstadt fahren. = different: the going would be spontaneous, not necessarily the deciding.

Can I omit the second wir and say … ob in die Innenstadt fahren?

No. German requires an explicit subject in subordinate clauses: ob wir in die Innenstadt fahren.

What’s the gender of Innenstadt, and why does it matter?

Innenstadt is feminine: die Innenstadt.

Accusative (motion): in die Innenstadt
Dative (location): in der Innenstadt
Genitive: der Innenstadt

What’s the difference between Innenstadt, Stadtzentrum, and City?

Innenstadt: everyday word for downtown/inner city.
Stadtzentrum: literal “city center,” a bit more formal/neutral (maps, signage).
City: in some places, colloquial for the central shopping district.
In most contexts, Innenstadt and Stadtzentrum are interchangeable.

Is it okay to add oder nicht after the ob‑clause?

Yes. Wir entscheiden spontan, ob wir in die Innenstadt fahren (oder nicht). oder nicht is optional and just makes the alternatives explicit.

Can I use a zu‑infinitive instead of ob?

You can, but it changes the meaning:

Wir entscheiden spontan, ob wir in die Innenstadt fahren. = we decide whether to go or not.
Wir entscheiden spontan, in die Innenstadt zu fahren. = we decide to go (we choose that option).
Keep ob if you want the whether/if meaning.

Any quick pronunciation tips?

entscheiden ≈ ent‑“shy”‑den (IPA: [ɛntˈʃaɪ̯dən])
spontan ≈ shpon‑TAHN (IPA: [ʃpɔnˈtaːn])
Innenstadt ≈ IN‑en‑shtat (IPA: [ˈɪnənˌʃtat])
fahren ≈ FAH‑ren (IPA: [ˈfaːʁən])
ob ≈ op (IPA: [ɔp])
Note: initial sp/st sound like “shp/sht” in standard German.

Is hinfahren better than just fahren here?

Both work. hinfahren adds a directional nuance (“go there by vehicle”):

… ob wir in die Innenstadt fahren. (neutral)
… ob wir in die Innenstadt hinfahren. (slightly more directional/colloquial)
Most speakers just say fahren.

How would I say it in the past (perfect)?

Wir haben spontan entschieden, ob wir in die Innenstadt fahren.
If you want to underline “would go,” you can say … ob wir in die Innenstadt fahren würden, but it’s often unnecessary.