Questions & Answers about Город сильно изменился за десять лет.
Why does изменился have a reflexive -ся ending?
In English, we can just say the city changed, but in Russian, the base verb изменить needs a direct object (to change something else). Adding -ся makes it intransitive, meaning the city changed itself. Although this lesson focuses on imperfective passive verbs, this is a perfective verb showing the final result of those changes!
Why do we use за десять лет instead of через десять лет for 'in ten years'?
Russian uses за plus the accusative case to show how long it took to complete an action (over the course of ten years). If you used через десять лет, it would mean ten years from now in the future.
Doesn't сильно usually mean 'strongly'? Why is it translated as 'a lot'?
That is its literal meaning! But when talking about verbs of change, growth, or feeling, Russian naturally prefers сильно to express 'a lot', 'heavily', or 'significantly'.
Why is the word for years лет instead of a plural form of год?
After numbers 5 and above, Russian requires the genitive plural case. The word год (year) is irregular here: its genitive plural borrows from the word лето (summer), becoming лет.