今年はいつ休暇を取りますか。

this year

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

to need; to want

indicates two contrasting actions; indicates possessive (often found in place names and compound words)

holiday; day off; furlough; absence (from work)

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to take; to pick up; to harvest; to earn; to win; to choose; to steal; to eat; to have (a meal); to remove (one's glasses, etc.); to compete (in sumo, cards, etc.); to play

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way