Questions & Answers about Cumpăr o carte joi.
In English we say 'on Thursday', but there is no word for 'on' in this sentence. Is it missing?
You don't need a preposition like 'on' before a day of the week in Romanian when talking about an action happening on that specific day. You just use the day itself, so joi simply translates to 'on Thursday' here.
Why isn't the word for Thursday (joi) capitalized?
Unlike in English, days of the week and months of the year are not capitalized in Romanian unless they happen to be the very first word in a sentence.
Why is there no word for 'I' (eu) before the verb?
Romanian often drops the subject pronoun because the verb itself changes to show who is doing the action. The form cumpăr already means 'I buy', so adding eu is entirely optional and usually left out.