Learn Romanian: Profesorul scrie acest document. - The professor writes this document.

We use acest because document is a neuter noun in the singular form. Acest is the form of "this" used for both masculine and neuter singular nouns, while această is used for feminine singular nouns.

Why isn't there a definite article on the end of document?

When a demonstrative adjective like acest comes directly before the noun, the noun stays in its simple form and does not take a definite article at the end. You just say acest document, never acest documentul.

Why does profesorul end in -ul?

In Romanian, the definite article (the word for "the") attaches to the end of the noun. Profesor is a masculine noun, so we add -ul to the end to make it profesorul, meaning "the professor".

What is the dictionary form of the verb scrie?

The dictionary form (the infinitive) is a scrie, meaning "to write". Here, it is in the third-person singular form because the action is being done by "the professor" (he/she writes).