Sawing logs is warm work.

锯木这工作干起来浑身发热。

It will be hard to work today—specially when it's so warm and sunny outside.

今天无心工作—尤其是外面这样风和日丽。

They lay snug and warm amid the blankets and watched their sister hard at work.

他们躺在温暖舒服的毯子中，看着姐姐辛苦地干活。

The problem: Humans want a warm (but not too warm) and dry place to live and work that has lots of light.

问题：人类需要在一个温暖（但不是太热）和干燥，光线充足的地方生活和工作。

You can't work with an average, squashing together the way heat radiation goes through the dense, warm, humid lower atmosphere with the way it goes through the thin, cold, dry upper atmosphere.

通过平均法计算是行不通的，即不能将热力在密实、温暖、潮湿的底层大气层中辐射的方式，与在稀薄、寒冷、干燥的上层大气层中的辐射方式混为一谈。