Bitter constraint, and sad occasion dear, Compels me to disturb your season due: For Lycidas is dead, dead ere his prime... Milton is lamenting, once again, that Milton has been compelled to begin writing.

因为亲友的惨遇，痛苦的重压，迫使我前来扰乱你正茂的年华：,利西达斯死了，死于峥嵘岁月。,弥尔顿再一次哀叹道，他是不得以写这首诗的。

耶鲁公开课 - 弥尔顿课程节选

You cannot say to me, "Take a force, due to a spring, and see what force it applies and divide by the acceleration and get the mass, " because we haven't defined force, either.

你不能说,"给弹簧施加一个力,看看它能提供多大的力,然后除以加速度,得到质量",因为我们还没给力下一个定义

耶鲁公开课 - 基础物理课程节选