During is the meaing, and during is better form (to me). Nothwithstanding that,
http://dictionary.cambridge.org/define.asp?key=39634&dict=CALD
"on" is improper unless it is specific.
http://dictionary.cambridge.org/define.asp?key=55337&dict=CALD
Which is correct
"In Jan 2009" or "On Jan 2009"
2 answers
Bob Pursley is right.
Use "in" when you are referring to anytime during a particular month or year.
In January 1960, she had her 17th birthday.
In 1997, the school gained several grants for partnership academies.
Use "on" when you are referring to a particular day/date in a month and/or year.
On September 4, 1992, my first grandchild was born.
A powerful typhoon hit Taiwan on July 28, 2008.
Use "in" when you are referring to anytime during a particular month or year.
In January 1960, she had her 17th birthday.
In 1997, the school gained several grants for partnership academies.
Use "on" when you are referring to a particular day/date in a month and/or year.
On September 4, 1992, my first grandchild was born.
A powerful typhoon hit Taiwan on July 28, 2008.
2 answers