Learn Hardcore Romanian: Pisica tristă devine fericită când primește haine calde pe pat. - The sad cat becomes happy when it receives warm clothes on the bed.

Because pisica is a feminine singular noun, the adjective must agree in gender and number. The masculine form is trist, but for a feminine singular subject you use tristă.

Why is fericită used instead of fericit?

For the same reason as above: fericită is the feminine singular form of the adjective fericit, matching pisica in gender (feminine) and number (singular).

Why do the adjectives follow the noun (Pisica tristă) instead of coming before it?

In Romanian the neutral position for attributive adjectives is after the noun. Placing tristă after pisica is the standard word order. You can sometimes front an adjective for emphasis, but here it follows the noun.

Why is there no definite article on pat or haine calde?

In Romanian you only add the definite article when you talk about a specific bed or the specific clothes already known to both speaker and listener. Dropping the article makes them indefinite (“a bed,” “some warm clothes”), which is fine if you’re talking in general terms.

Why is pe used before pat instead of în?

Romanian uses pe to express “on” when referring to horizontal surfaces (on the table = pe masă, on the bed = pe pat). În would mean “in” or “inside.”

Why are both devine and primește in the present tense?

The sentence describes a general or habitual situation (“the sad cat becomes happy whenever it receives warm clothes on its bed”). Romanian uses the present indicative in both main and subordinate clauses to express such recurring or timeless actions.

Why isn’t there a subject pronoun (like ea) before devine?

Romanian is a pro-drop language: verb endings already indicate person and number. Since devine ends in ‑e (third person singular), adding ea (“she”) is unnecessary and usually omitted.

Why is calde used instead of cald?

Haine (“clothes”) is a feminine plural noun, so the adjective cald (warm) must agree and take its feminine plural form calde.

Why is a primi used without a preposition before haine calde?

The verb a primi (“to receive”) is transitive in Romanian and takes a direct object. You do not need a preposition before haine calde.

What are the little marks on letters (ă in tristă, â in când, etc.)?

Those are Romanian diacritics. Ă (ă) represents a mid-central vowel sound; Â (â) is another specific vowel. They distinguish words and pronunciation (for example, cand without diacritics could be misread), so they’re important.