The duration of the disease can vary from a few weeks to many months or even years.

The duration of the conference varied between 2 and 4 days.

The duration of these effects varies by class and level.

The duration of those effects varies but can range from a few minutes to an hour.

Duration of symptoms varied from two months to 15 years.

The duration varies according to the student's course, and other personal circumstances.

The daily duration of sleep varies, usually 12-16 hours, with 13-14 being the average.

Therefore, the duration of a flight test program can vary from a few weeks to many years.

This meant that the duration of hours varied with the season.

The duration of the symptoms varies, but is usually one or two weeks.