Breakdown of В две тысячи пятом году они открыли филиал и подписали важный договор.
и
and
они
they
важный
important
год
year
Questions & Answers about В две тысячи пятом году они открыли филиал и подписали важный договор.
Why does the word for year end in -у (году) instead of the usual Prepositional ending -е?
The word год (year) belongs to a special group of short masculine nouns that take an irregular -у ending in the Prepositional case when used with the prepositions в (in) or на (on/at). Because we are saying "in the year," it must be в ... году.
Why is only пятом (fifth) in the Prepositional case, while две тысячи (two thousand) doesn't change?
When talking about years in Russian, we use ordinal numbers (meaning "the two thousand and fifth year"). For compound numbers like this, only the very last word changes its ending to match the case. So, две тысячи stays exactly the same, and only пятый changes to its Prepositional form, пятом.
Are филиал (branch) and важный договор (important contract) in the Nominative case here?
They are actually in the Accusative case, because they are the direct objects receiving the actions of being opened and signed. However, for masculine inanimate nouns (non-living things), the Accusative case form looks exactly identical to the Nominative dictionary form.
Why are the verbs открыли (opened) and подписали (signed) in the perfective aspect?
Perfective verbs are used here because these represent completed, one-time achievements in the past. They also form a sequence of events (they opened a branch, and they signed a contract), which is a common reason to use a series of perfective verbs.