We useduringto say when something happens, if it happens in or over a period of time. We useforto talk about the length of time something lasts.
| They went at one point in the winter. |
| They went from the beginning to the end of the winter. |
She phoned meduringthe week to tell me that she was getting married.(referring to a point in the week)
We were in the cinemaforthree and a half hours.
Not: …during three and a half hours.
Our flight to New York was delayedforseven hours.
Not: …during seven hours.
We went to Italyfora week.
Not: …during a week.
We can also useforto refer to public holidays and seasons:
He always goes to his mother’s houseforNew Year.
Not: …during New Year.
See also:
For
During