Learn Hardcore Italian: Dopo che ho finito la lezione, bevo acqua in giardino. - After I finish the lesson, I drink water in the garden.

In Italian, when you link two clauses and the second clause has a finite verb, you need che after dopo:
• Correct: Dopo che ho finito la lezione,…
• Incorrect: Dopo ho finito la lezione,…
If you want to drop che, you must use a non-finite form:
• Dopo aver finito la lezione,…
• Dopo la lezione,… (using a noun phrase)

What’s the difference between Dopo che ho finito la lezione and Dopo aver finito la lezione?

Both express “after finishing the lesson,” but:
• Dopo che ho finito… uses a finite verb (ho finito) and is very common in speech and informal writing.
• Dopo aver finito… uses an infinitive construction (aver finito) and sounds slightly more formal or literary.
Meaning-wise they’re interchangeable.

Why is the first verb in the passato prossimo (ho finito) but the second in the present tense (bevo)?

Italian often mixes a completed action with its immediate result or habitual follow-up in the present tense. Here it can mean either:
• A one-time sequence: “After I have finished the lesson, I drink water in the garden.”
• A routine: “Whenever I’ve finished the lesson, I drink water in the garden.”
If you meant two past events on the same day, you’d say: Dopo che ho finito la lezione, ho bevuto acqua in giardino.

Could I use the future tense in the second clause (for example berrò acqua)?

Only if you want to emphasize that the drinking is strictly in the future, not immediate or habitual. Normally Italians use the present to describe immediate consequences or routines. Saying berrò acqua sounds more like “At some point later I will drink water,” and is less natural in this context.

Why is there no article before acqua? Can I say Bevo dell’acqua or Bevo l’acqua instead?

• Bevo acqua is a general/indefinite statement: “I drink water” (in general or right now).
• Bevo dell’acqua uses the partitive (some water) and highlights “some amount of water.”
• Bevo l’acqua means “I drink the water” (a specific water, e.g. the bottle on the table).
All three are correct, but each has a slightly different nuance.

Why do we say in giardino instead of nel giardino or al giardino?

When you speak of a place where you habitually are or perform an action, Italian often omits the article:
• in giardino = “in the garden” (general location).
Adding an article (nel giardino) makes it more specific (“inside that particular, maybe enclosed garden”). Al giardino is less common for private gardens and often refers to “to the public park/garden.”

Is the comma necessary after the subordinate clause?

Yes. When a subordinate temporal clause (Dopo che ho finito la lezione) comes before the main clause, you separate them with a comma. If you reversed the order, the comma could be optional:
• Bevo acqua in giardino dopo che ho finito la lezione.

Must I use the indicative after dopo che, or could I use the subjunctive?

Temporal conjunctions like dopo che always take the indicative in Italian. Using the subjunctive (che abbia finito) is ungrammatical here. You keep it simple with dopo che + indicativo.