Они никогда не забывают ключи.

They never forget keys.

Breakdown of Они никогда не забывают ключи.

• ключ: the key
• они: they
• никогда: never
• забывать: to forget

Questions & Answers about Они никогда не забывают ключи.

Why is there both никогда and не in the sentence? It seems like double negation.

In Russian, negative adverbs like никогда (never) must be paired with the negative particle не on the verb. You always say никогда не забывают rather than dropping не. Together they express a single negation (“never forget”).

There’s no word for their before ключи. How do you express “their keys”?

Russian often omits possessives when context makes ownership clear. If you want to specify, use the reflexive possessive свои (their own):
• Они никогда не забывают свои ключи.
You could also say их ключи, but with the subject as owner, свои is more natural.

Why aren’t there any articles like the or a before ключи?

Russian does not have articles. Whether ключи is “keys,” “the keys,” or “some keys” is determined by context, word order, or additional words (like эти for “these keys,” etc.).

What case is ключи in, and how do you tell?

Ключи is in the accusative plural (direct object). For inanimate nouns, the nominative and accusative plural look the same, so you rely on word order (noun follows the verb) and meaning to see it’s the object.

Why is the verb забывать in the imperfective aspect? How would you express a one-time event?

Забывать is imperfective, used for habitual or repeated actions – here, they never forget. For a single event you’d use the perfective забыть.
Example (future perfective): Они никогда не забудут ключи.

Can you leave out они and just say Никогда не забывают ключи?

Yes. Russian often drops subject pronouns because the verb ending (–ют) makes it clear it’s 3rd person plural. Including они adds clarity or emphasis; without it you might wonder who is meant.

Is the word order fixed? Could you say Никогда они не забывают ключи or Они не забывают никогда ключи?

Word order is fairly flexible. The neutral order is Они никогда не забывают ключи.
• Никогда они не забывают ключи puts focus on never (“Never do they forget the keys”).
• Они не забывают никогда ключи is less natural and would oddly shift emphasis between never and keys. Typically you keep никогда right before не забывают.

How would you say They have never forgotten the keys (present perfect) in Russian?

Russian has no present perfect tense. You use the past imperfective for life‑to‑date experience:
• Они никогда не забывали ключи.
To stress “up to now,” add еще:
• Они еще никогда не забывали ключи — they have never forgotten the keys yet.