1. sometimes, occasionally, at times, from time to time, now and then, once in a while, at intervals
2. seasonal, of the season, appropriate (for the season or occasion)
1. at (place, time), in, on, during
2. to (direction, state), toward, into
3. for (purpose)
4. because of (reason), for, with
5. by, from
6. as (i.e. in the role of)
7. per, in, for, a (e.g. "once a month")
8. and, in addition to
9. if, although