Examples of using "серьезное" in a sentence and their english translations:
Things have gotten serious.
That's a gross mistake.
- The situation is grave.
- The situation is serious.
It's a very serious illness.
but of course there is something much more serious about these questions.
"Tom, there is something I want to talk to you about..." "Yes, what is it? Is it something serious?" "Yes, sort of..."