Learn Romanian: Băiatul desenează toamna.

In Romanian, the word for "the" (the definite article) is attached to the end of the noun rather than being a separate word before it. For most masculine singular nouns like băiat (boy), you add -ul to say "the boy" (băiatul).

Why does the verb desenează end in -ează?

The dictionary form of the verb is a desena (to draw). Many Romanian verbs that end in -a take a special ending (-ează) for the "he, she, or it" forms. This is a very common pattern, so el desenează means "he draws".

The dictionary word for autumn is toamnă with an ă. Why is it toamna in this sentence?

Just like -ul makes băiat mean "the boy", adding an -a to the end of a feminine noun makes it mean "the". When a feminine noun ends in -ă, that letter simply changes to a regular -a. So, toamnă (autumn) becomes toamna (the autumn).

I previously learned that toamna means "in the autumn". Could this sentence actually mean "The boy draws in autumn"?

Yes, absolutely! In Romanian, toamna can mean both "the autumn" (as the object he is drawing) and "in the autumn" (as the time when he is drawing). Without more context, this exact sentence can mean either "The boy draws the autumn" or "The boy draws in the autumn."