a4esl.org/q/h/9807/km-sincefor

http://a4esl.org/q/h/9807/km-sincefor.html

For or Since

For is used for general periods of time - 2 hours, three days, one month.
Since is used for a specific time - 1998, January, last week, one month ago. Click the answer button to see the correct answer.