leap year: うるう年;
literally: 文字どおりに，逐語的に;
leap: ～を跳び越える;
hence: それゆえ, したがって;
occur 起る:生じる
introduce: ～を導入する;
********************
This year is a special year for all of us. February sees an extra day added to our calendar giving us one more day of work, rest or play. The name leap year comes from the fact that hundreds of years ago the leap year day did not exist in English law. Literally, the day was ‘leapt over’ or ignored, hence the term ‘leap year’. They occur every four years. It is said that Julius Caesar introduced Leap Years in the Roman empire over 2000 years ago, but the Julian Calender had only one rule: any year evenly divided by 4 would be a leap year. But this led to too many leap years. Now the Gregorian Calendar – the modern calendar, calculates a Leap Year if:
1) The year is evenly divisible by 4;
2)If the year can be evenly divided by 100,
it is NOT a leap year, unless;
3) The year is also evenly divisible by 400.
Then it is a leap year. (by Prof. Simon Smith)
********************