We could not afford to overlook such a serious offence.

对这样严重的违法行为，我们决不能视若无睹。

《牛津词典》

Driving with excess alcohol in the blood is a serious offence.

血液里酒精含量过高时驾车是严重的违法行为。

《牛津词典》

Driving while drunk is a serious offence.

酒醉驾车是严重违章。

youdao

It is not, any longer, treated as a serious offence, unless it is repeated.

ECONOMIST: Daft about drugs

The court heard that, while Harratt did not know exactly what Otak had done, he must have realised that he had committed a serious offence.

BBC: Steven Harratt jailed for assisting Wakefield murderer

He said there were guidelines for exceptional circumstances where a caution was appropriate even for a serious offence, such as the mental health or the age of the offender.

BBC: Police cautions under review, says Ministry of Justice