В этот раз я не опоздал на семинар.

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Breakdown of В этот раз я не опоздал на семинар.

• не: not
• на: for
• опоздать: to be late

Questions & Answers about В этот раз я не опоздал на семинар.

Why does Russian say В этот раз? Is it the same as На этот раз?

Both are common and usually translate as this time, but they’re not always interchangeable.

• В этот раз = this time / on this occasion (neutral, very common).
• На этот раз often has a slight contrastive feeling: this time (as opposed to other times) / for once / this time around. In your sentence, В этот раз я не опоздал... is fully natural; На этот раз я не опоздал... is also natural and can sound a bit more “contrasting.”

What case is этот раз, and why?

раз is masculine, so этот is the masculine nominative/accusative form.
In В этот раз, the preposition в is used with the accusative to mean “at a time/occasion” (a “point in time” usage). So it’s в + accusative: в этот раз.

Why is there я? Can it be omitted?

Yes, я is optional because the verb ending already shows the subject in past tense by gender/number (and context).

• В этот раз не опоздал на семинар. = perfectly fine in conversation. You keep я when you want emphasis/contrast: I (not someone else) wasn’t late.