跑步时膝盖突然疼了起来。

My knee suddenly ___hurts when I run.

看到朋友不信任的眼神让我很受伤。

Seeing the distrust in my friend's eyes really ___hurts.

熬夜学习对你的健康有负面影响。

Staying up late to study ___hurts your health.

我的脚受伤了，现在走路很疼。

My foot ___hurts when I walk now.