Breakdown of Он совершил серьёзную ошибку.
Questions & Answers about Он совершил серьёзную ошибку.
Совершил is the past tense of совершить, so the sentence is talking about something that already happened.
Why not совершает?
- совершает = is committing / commits
- That would make the sentence present tense: He is committing a serious mistake or He commits a serious mistake
Why not сделал?
- сделать means to do / make, and in some contexts it can work with ошибка, especially in the phrase сделать ошибку, but совершить ошибку is a very common and natural collocation in Russian, especially in slightly more formal or standard language.
- So совершил ошибку sounds like committed/made a mistake, with совершить being the usual verb here.
Here совершить means to commit or to carry out.
It is often used with nouns that describe an action or act, for example:
- совершить ошибку — to make/commit a mistake
- совершить преступление — to commit a crime
- совершить поездку — to make/take a trip
So in this sentence, it does not mean something like to perfect or to complete oneself. It simply forms a natural expression with ошибка.