Learn Hardcore Russian: Подумай о своих целях в жизни.

In Russian, the verb думать (to think) takes the preposition о (about) and requires the prepositional case. The noun цель (goal) in the prepositional plural becomes целях, so о целях literally means “about (the) goals.” Because we’re talking about your own goals, it becomes о своих целях (“about your own goals”).

Why is the possessive своих used instead of твоих?

свой is the reflexive possessive pronoun that always refers back to the subject (here the implied ты in the imperative). It’s more neutral and idiomatic when the owner of something is the same as the subject. Using твой (your) would still make sense, but свои is preferred in this structure.

Why is жизни in this sentence, and why not жизнь or жизней?

After the preposition в meaning “in” (indicating context or location), Russian uses the prepositional case. The feminine noun жизнь (life) in the prepositional singular becomes жизни, so в жизни means “in life.”

What’s the difference between Подумай and Думай in imperatives?

думай is the imperfective imperative, implying “keep thinking” or “think continuously.”
подумай is the perfective imperative, suggesting a one-time action: “take a moment to think about something.”
Here Подумай tells the listener to pause and consider their goals.

How would I make this sentence polite or address more than one person?

Use the formal/plural imperative ending -йте. The sentence becomes:
Подумайте о своих целях в жизни.
This form works both for polite singular “you” and for “you all.”

Why isn’t there a subject pronoun like ты in the sentence?

In Russian imperatives, the subject (“you”) is almost always omitted because it’s understood from the verb ending. Подумай inherently means “(you) think” or “(you) give thought.”

Can I use над plus the instrumental case instead of о plus the prepositional?

Yes. You could say Подумай над своими целями в жизни using над + instrumental (целями).
Nuance:
• думать о чём (about something) is more general “think about.”
• думать над чем (over something) often suggests deeper pondering or problem-solving.

Is the word order flexible? What if I say Подумай в жизни о своих целях?

Russian word order is quite flexible, but clarity and emphasis matter.
• Подумай о своих целях в жизни groups the verb, object, and context in a natural flow (“think about your goals” + “in life”).
• Подумай в жизни о своих целях is grammatically correct but less idiomatic, as it separates the key phrase о своих целях with в жизни at the front, which may sound awkward.