Questions & Answers about Вчера ЕС закрыл границу.
Why does the verb закрыл take the masculine past tense form here?
Because the subject is the acronym ЕС (the EU). To find the gender of an indeclinable acronym in Russian, you look at the gender of its main underlying word. ЕС stands for Европейский союз (European Union). Since the core noun союз is masculine, the acronym ЕС is treated as masculine, which is why it pairs with the masculine verb закрыл.
How do you pronounce ЕС in this sentence?
It is pronounced as individual letter names: е-эс (ye-es). Even though it looks like it could be read as a single syllable, it is an initialism, so you read the standard names of the Russian letters.
If I wanted to say something like "inside the EU" or "from the EU," would the ending of ЕС change?
No, ЕС is an indeclinable acronym. This means its spelling and pronunciation never change, no matter what grammatical case the sentence requires. "In the EU" is simply в ЕС and "from the EU" is из ЕС.
Why does the word граница change to границу here?
The border is the direct object receiving the action of the verb закрыл (closed). Because of this, it must be in the accusative case. For feminine nouns ending in -а like граница, the accusative ending changes to -у.