Questions & Answers about Однажды я встретил актрису в трамвае.
Однáжды means “once / one day (in the past)” and is usually used for telling a specific story or anecdote.
- однáжды – stylistically neutral, common in both speech and writing: “One day, I…”
- один раз – more literally “one time”, often more matter‑of‑fact or counting: “I did it one time, not twice.”
- как-то раз – more colloquial, story‑like: “So, once...”, “One time…”
In this sentence, однáжды sets up a little narrative: “One day I met an actress…”
Putting однáжды first is very natural: it sets the time frame, like English “One day, I met…”.
You can move it:
- Я однáжды встрéтил актри́су в трамвáе. – I once met an actress on a tram.
- Я встрéтил однáжды актри́су в трамвáе. – possible, but sounds marked; the adverb feels oddly inserted.
The most natural positions are at the very beginning or right after “я”. At the end (встретил актрису в трамвае однажды) is also possible but sounds a bit “afterthought‑ish”.