As mentioned in our ずに lesson, ず is an
auxiliary verb that is not commonly used in modern Japanese, except for in set expressions. It has the equivalent role of ない, in expressing that something 'has not', or 'will not' happen. The
case marking particle に is then combined with the
adverbial particle は, and the negative-potential form of いる, いられない.
ずにはいられない may be translated as 'cannot help doing (A)', or 'cannot resist doing (A)'.
ずにはいられない will be attached to the
indeterminate form of verbs. This is the same stem form as ない uses.
美味（おい）しそうなステーキが目（め）の前（まえ）にあったら、食（た）べずにはいられない。
If there is a delicious looking steak in front of me, there is no way I can resist eating it.
この映画（えいが）を見（み）ると誰（だれ）でも泣（な）かずにはいられない。
No matter who you are, if you watch this movie, there is no way you can not cry.
Although
ずにはいられない is often translated as 'cannot resist (A)', the literal meaning is simply 'cannot be without (A)'.
As the modern
indeterminate form of
する has several different forms, care will need to be taken when conjugating
する verbs. While ない joins with し to create しない, ず will join with せ to create せず.
この10年間（ねんかん）色々（いろいろ）とお世話（せわ）になったから、先輩（せんぱい）には感謝（かんしゃ）をせずにはいられない。
This past 10 years, I have been helped a lot by my senpai, so there is no way I can go on without showing them some appreciation.
私（わたし）は猫（ねこ）アレルギーなのでくしゃみをせずにはいられない。
I am allergic to cats so I can't not sneeze.