一月大，二月小，三月大，四月小，五月大，六月小。。。。

月份“大”或“小”其实是说某月有“偶数月底”或有“奇数月底”：一月有31天，二月有28天等等。

所以，中文用“大”“小”表示“奇数”“偶数”，而英语则直接用“奇”(odd)“偶”(even)表达“月份”：

An odd month

An even month

Janauary is an odd month.

February is an even month.

March is an odd month.

April is an even month.

May is an odd month.

June is an even month.

July is an even month.

August is an even month.

September is an odd month.

October is an even month.

November is an odd month,and

December is an even month.

最后，用英语表达什么是odd number，什么是even number：

Well,an odd number such as 13579 is an number that cannot be divided(被除) by 2.

Well,an even number such as 2468 is an number that can be divided(被除) by 2.

这是用英语表达和用英语与人沟通“奇数”“偶数”必须守住的“底线”，你可以忘记odd,or even，但你连be divided by 2都不能表达，那么你就真的无法用英语与人交流了。

也可以这么来表达odd, or even“练口语”：

If a number can not be divided by 2, it is an odd number such as 13579

If a numbet can be divided by 2, it is an even number such as 2468.

什么是“闰年”a leap year呢？

相信时间一久，你肯定又把leap year这个词给忘记了。

那么，你这么表达a leap year或者“闰年”吧：

Well, a yesr is a leap yesr when there are only 28 days in February in that year.