in [month]
表示月份前通常用介词in。
The meeting is in January.
会议在一月举行。
一月
一年的第一个月；冬至后10天开始
一年的第一个月；冬至后10天开始
the first month of the year; begins 10 days after the winter solstice
The new semester starts in January.
新学期在一月开始。
用法提示：January 是名词，表示“一月”，在句中作时间状语。
My sister was born in January.
我妹妹出生在一月。
用法提示：January 是名词，表示“一月”，在句中作时间状语。
January has thirty-one days.
一月有三十一天。
用法提示：January 是名词，表示“一月”，在句中作主语。
表示月份前通常用介词in。
The meeting is in January.
会议在一月举行。
日期序数词前可省略介词on。
My birthday is January 15th.
我的生日是一月十五日。
last表示去年的同一个月份。
I visited Beijing last January.
我去年一月去了北京。
next表示明年的同一个月份。
We plan to move next January.
我们计划明年一月搬家。
January (一月) is a month; janitor (看门人) is a person who cleans and maintains a building.
January (一月) is the first month; February (二月) is the second month.
在一月
The new semester starts in January.
新学期在一月开始。
一月促销
I bought this jacket during the January sales.
我是在一月促销时买的这件夹克。
一月初
We plan to travel in early January.
我们计划一月初去旅行。
一月底
The project is due in late January.
项目一月底截止。
一月一日
January 1st is New Year's Day.
一月一日是元旦。
一月的天气
The January weather here is very cold.
这里一月的天气很冷。
noun
adjective
root
suffix
一月是新年开始的月份
一月通常是一年中最冷的月份之一
人们常在一月制定新年计划
北半球一月常有降雪
一月是日历的第一个月
一月效应（股市中一月股价上涨的现象）
The January effect is often attributed to year-end tax considerations.
一月效应通常归因于年终税收考虑。
一月解冻（一月出现的短暂温暖天气）
We experienced a January thaw that melted all the snow.
我们经历了一月解冻，融化了所有的雪。
一月忧郁（假期结束后的低落情绪）
She's suffering from the January blues now that the festivities are over.
节日结束后，她正遭受着一月忧郁的困扰。
一月，厌倦了事情的发展方式
The song 'January' by Pilot starts with the line 'January, sick and tired of the way things are going'.
Pilot乐队的歌曲《January》以‘January, sick and tired of the way things are going’开头。
Dictionary facts from ECDICT.