立冬标志着秋天的结束，

Beginning of Winter means that autumn has come to an end. 

在古籍中，秋天收获的各种庄稼到了立冬都已经晒干储存，动物纷纷躲起来，开始冬眠。

In the ancient books, all kinds of crops harvested in autumn have been dried and stored and animals have already hidden and started to hibernate during the season. 

立冬也意味着天气越来越冷，所有生物新陈代谢减缓，躲避冬天的严寒。

At this time, the weather is getting cold and all the creatures have begun to slow down their rate of metabolism to keep themselves safe from the coldness in winter.