将给定的文章按照日期和重要性进行分类。
August 25th, 2020 - A new COVID-19 vaccine shows promising results in early tests.

November 3rd, 2020 - The United States Presidential election takes place.

December 1st, 2020 - The World Health Organization warns that the COVID-19 pandemic is still accelerating.
August 25th, 2020 - A new COVID-19 vaccine shows promising results in early tests.
December 1st, 2020 - The World Health Organization warns that the COVID-19 pandemic is still accelerating.
November 3rd, 2020 - The United States Presidential election takes place. 

Classified by date, in descending order: 
December 1st, 2020
November 3rd, 2020
August 25th, 2020

Classified by importance, in descending order:
December 1st, 2020 
November 3rd, 2020 
August 25th, 2020