Наречия Времени и Места - Наречия низкой частоты

not at any point in time

никогда

on any occasion

всегда, когда-либо

in a manner that almost does not occur or happen

вряд ли когда-нибудь

for one single time

один раз

for a single instance

один раз, разок

for two instances

два раза

on a very infrequent basis

редко

used to refer to something that happens rarely or infrequently

редко

on very rare occasions

редко, в редких случаях

in an infrequent and unpredictable manner

спорадически, непостоянно

not on regular occasions

недостаточно часто, необычно

not on a regular basis

время от времени

on irregular but not rare occasions

порой

on occasions that are not regular or frequent

время от времени

at moments that are not constant or regular

время от времени, порой

at infrequent intervals

периодически, изредка

at irregular intervals

периодически, временами