sometimes (on some occasions, but not always): Sometimes I walk to work.
occasionally (in an occasional manner; not regularly): We dine out occasionally.
from time to time (occasionally): We visit him from time to time.
every so often (from time to time): I see her every so often at the club.
once in a while (in an occasional manner; not regularly): We meet for a drink once in a while.
now and then (sometimes but not very often): I talk to her on the phone now and then.
at times (on some occasions, but not always): At times, it’s difficult to understand her.
