Very serious
严重───serious;极───extremely
He's quite a serious person.───他是一个相当严肃的人。
consequences could be serious.───后果可能是严重的。
You're joking. Are you serious?───你在开玩笑吧。你是认真的吗？
He and his wife have never had a serious quarrel. Through mutual indifference they've just drifted apart.───他和妻子从未激烈地争吵过，但相互间漠不关心，只好分手。
After Imjin battle, Ming dynasty was into a serious political and economic crisis, and it was perished less than fifty years after the war.───经过壬辰一役，明王朝陷入了严重的政治经济危机之中，战后不到五十年即告灭亡。
He made a serious mistake in spelling. Can you point it out?───他犯了一个宽峻的拼写弊端，您能指出去吗？
No serious historian today accepts this theory.
What's up - why does everyone look so serious?
A superficial injury is not serious.
Even a superficial inspection revealed serious flaws.
They pose a serious threat to security.