Я взял не тот ключ и не смог открыть дверь.

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Breakdown of Я взял не тот ключ и не смог открыть дверь.

• открыть: to open
• дверь: the door
• и: and

Questions & Answers about Я взял не тот ключ и не смог открыть дверь.

Why is it взял and not взяла or взяли?

Because the past tense in Russian agrees with the speaker’s gender and number.

• взял = masculine singular
• взяла = feminine singular
• взяли = plural

So Я взял... means the speaker is male.
If a woman says it, she would say Я взяла не тот ключ и не смогла открыть дверь.

Why do we use взял here, not брал?

взял is the perfective past form of взять, while брал is the imperfective past form of брать.

Here, взял is used because the sentence describes one completed action: the speaker took a key.

• Я взял не тот ключ = I took the wrong key.
• Я брал не тот ключ would sound more like I was taking / used to take the wrong key, or it would shift attention away from the completed result.

In this context, the completed action matters, because it led to the next result: the speaker couldn’t open the door.

What does не тот ключ literally mean, and why does it mean the wrong key?