In 1968, the group Blood, Sweat and Tears recorded this gentle, sad song about winter.

VOA: special.2009.01.26

Now, we are very gentle in this course with respect to knowing integrals, but this is one you have to know.

这门课对积分,的要求并不高，但这个积分你们必须会算。

麻省理工公开课 - 热力学与动力学课程节选