Breakdown of Ему надо отдохнуть во время перерыва.
он
he / it (for a masculine noun) / it (for a neuter noun)
надо
must, need to
перерыв
break
отдохнуть
to rest (perfective)
Questions & Answers about Ему надо отдохнуть во время перерыва.
Why is перерыва in the genitive case?
The prepositional phrase во время (during) always requires the following noun to be in the genitive case. Since перерыв (break) is a masculine noun ending in a consonant, we add -а to make it перерыва.
What does во время literally translate to?
It literally means "in the time [of]". The word во is a variation of в (in), and время (time) is in the accusative case here. Because it literally means "in the time of", it makes sense that the noun following it must be in the genitive case.
Why does the sentence start with Ему instead of Он?
Words expressing necessity, like надо or нужно, use an impersonal construction in Russian. The person who needs to do something must be in the dative case. Ему is the dative form of он (he), making the literal translation "To him it is necessary to rest."
Why is the perfective verb отдохнуть used here instead of the imperfective отдыхать?
The perfective отдохнуть is used because the focus is on achieving a complete result: getting some rest. If the speaker wanted to emphasize the continuous process of resting for the entire duration of the break, they would use the imperfective отдыхать.