Why only 28 days in February?
为什么二月份只有28天?
The reason can be traced back to ancient Rome.
原因可以追溯到古罗马。
In the 8th century BC,the Romans used the calendar of Romulus,a ten month calendar that kicked the year off in March with the spring equinox, and ended in December.
公元前8世纪，罗马人使用罗穆卢斯历法，该历法有十个月，从三月春分开始到十二月结束。
January and February didn't even exist.
1月和2月甚至都不存在。
The calendar year was only 304 days long.
该历法下，一年只有304天。
Back then, winter was a nameless monthless period that no one cared for.
在当时，冬天没有名字、没有月份也没人关心。
The calendar was primarily used as a timetable for planting and harvesting agriculture.
该历法主要用作农业种植和收获的时间表。
To farmers, winter wasn't worth counting·
对农民来说，冬天不值得考虑。
So for 61 days out of the year, Romans couldask, what month is it?
所以，对于一年中的61天，罗马人可能会问，现在是几?
And you could correctly answer, none!
你可以正确地回答，没有月份!
King Numa Pompilius thought that was stupid.
国王努玛蓬皮留斯认为这很愚蠢。
Why have a calendar if you're going to neglect one sixth of the year?
如果忽略一年中的六分之一，为什么还要日历呢?
So in 713 BC, he lined the calendar up with the years twelve lunar cycles, a span of about 355 days.
所以，公元前713年， 他用12个农历周期(大约355天)排列了该日历。
And introduced January and February.
并引入了一月和二月。
The months were added to the end of the calendar, making February the last month of the year.
这两个月份被添加到日历的末尾，二月便成了一年的最后一个月。
However the Romans were highly superstitious.
然而，罗马人非常迷信。
They believed even numbers were unlucky,and invited attacks from evil spirits.
他们认为偶数不吉利，会招来邪灵的攻击。
So Numa tried to make each month odd.
所以，努玛试着让每个月的天数都为奇数。
But to reach the quota of 355,one month hadto be even.
但要达到355天这一固定天数，某-个月的天数必须是偶数.
February ended up pulling the short stick.
结果是2月份吃亏。
Probably because it was simply the last month on the list.
可能因为二月是该日历的最后一个月。
Of course, a 355 day calendar had its bugs.
当然，355天的日历也有缺陷。
After а few years went by,the seasons and months would fall out of sync.
几年后，季节和月份就不同步了。
Summer would arrive in October and winter would end up in June.
10月是夏天，6月是冬天。
So to keep things straight,the Romans would occasionally insert а twenty seven day leap month,called Mercedonius.
所以，为了让该日历更清楚，罗马人偶尔会插入一个27天的闰月，即“Mercedonius (拉丁语闰月)’
The Romans would erase the last couple days of February,and start the leap month on February 24.
罗马人会抹去2月的最后几天,并在2月24日开始闰月。
Further evidence that no one ever cared much for February.
更多证据表明，没有人对2月份感兴趣。
This caused headaches everywhere.
闰月给各地带来了麻烦事。
The leap month was inconsistent,mainly because Rome's high priests determine when it would arrive.
闰月时间不一致，主要是因为罗马的大祭司决定它何时到来。
Not only did they insert Mercedonius randomly,but the priests being politicians abused the power,using it to extend the terms of friends and trim the terms of enemies.
他们不仅随意插入闰月，而且身为政客的牧师也滥用权力，利用它来延长朋友的任期，削减敌人的任期。
By Julius Caesar's time,the Roman people had no clue what day it was.
到了尤里乌斯.凯撒时代，罗马人根本不知道日子是哪一天。
So Caesar looked back to the solar calendar of the Egyptians to reform his calendar.
所以，凯撒回顾了埃及人的阳历改革他的历法。
Tо get Rome back on track,the Year 46 BC had to be 445 days long.
为了让罗马回到正轨，公元前46年必须是445天。
Caesar aligned the calendar with the Sun and added a few days.So that everything added up to 365.
凯撒以太阳为参照编排日历，并增加了几天。所以，所有天数加起来是365天。
February which by now is at the top of the calendar kept its 28 days.
现在，2月是该日历的开始，保持28天不变。
However it takes 365.24 days for the earth to make a complete rotation around the Sun.
然而，地球绕太阳一周需要365.24天。
That extra 0.24 days adds up to just about one full day every four years.
这额外的0.24天加起来大约是每四年凑够一天。
So once every four years,February gets an extra 29th day,also known as leap year day.
所以每隔四年，二月就有一个额外的第29天，也被称为“闰年日”。
But 0.24 times 4 doesn't quite make a full day.
但是，0.24乘以4不够一 整天。
So to make sure that we don't get ahead of ourselves,once every 100 years we skip leap year day.
所以，为了确保我们不会超越自己，每100年 我们就跳过一次闰年。
So these are the origins of our chaotic calendar.
这些就是我们混乱日历的起源。
It may not be pretty but it does seem to work now.
它可能不尽善尽美，但现在看起来确实有效。