2020年是一个闰年。

The year 2020 was a leap year.

今年是平年，不是闰年。

This year is a common year, not a leap year.

闰年每四年出现一次。

A leap year occurs every four years.

二月在闰年有29天。

February has 29 days in a leap year.

下一次的闰年将在2024年。

The next leap year will be in 2024.

二月有28天，闰年时有29天。

February has 28 days, 29 in a leap year.

平年的日历和闰年的日历不同。

The calendar of a common year is different from that of a leap year.

闰年有366天，而不是365天。

A leap year has 366 days instead of 365.

二月份有28天，闰年则有29天。

February has 28 days, and 29 days in a leap year.

公历每年有365天，闰年有366天。

The Gregorian calendar has 365 days in a year and 366 days in a leap year.