Adverbs of Low Frequency

not at any point in time

She never eats meat; she's been vegetarian since birth.

at any point in time

If ever you need help, just call me.

in a manner that almost does not occur or happen

She hardly ever misses her morning jog.

for one single time

I only ate sushi once in Japan.

for a single instance

She won the lottery one time.

for two instances

She visited the museum twice.

on a very infrequent basis

She rarely eats sweets, preferring fruit instead.

used to refer to something that happens rarely or infrequently

She seldom watches television.

on very rare occasions

She infrequently checks her email on weekends.

at irregular and unpredictable intervals of time

The old radio broadcasts sporadically, cutting in and out.

in a way that is rare or not customary

She uncommonly forgets her keys; she's usually very organized.

not on a regular basis

She visits her grandparents occasionally.

on irregular but not rare occasions

She enjoys a dessert now and then.

on occasions that are not regular or frequent

They visit their hometown now and again.

at moments that are not constant or regular

She can be a bit reserved at times.

at infrequent intervals

The team practices indoors on occasion.

now and then or from time to time

The professor periodically updates the syllabus, adding new readings when relevant research emerges.