This condition leads to a very sudden onset of blindness, which occurs over a period of a few days to several weeks. (cspca.com)
Since you might be completing the course over a period of a few days or weeks you will find there that you are tested as you complete each chapter. (comedyoffensivedriving.com)
Some babies breastfeed after one bath and some need to take three or four baths over a period of a few days, before they start nursing again. (modernmom.com)