他严肃的表情让所有人都紧张起来。

His ___stern expression made everyone nervous.

经理对项目延误提出了严厉的批评。

The manager issued ___stern criticism regarding the project delays.

他严厉地瞪了他妹妹莎拉一眼，但这并没有阻止她恶意地咧嘴笑。

He shot his sister Sarah a ___stern look which did not deter her from grinning maliciously.