This Sunday's worksheet is a nice little story knocked together by my talented 婚約者, Laura. It makes use of a typically English scenario (easily converted to your home country) to practice the appropriate use of "was" and "were".
Here's the sheet to download. Depending on ability it will take something around 10-15+ minutes.
As always, use this as many times as you want, but please don't redistribute anywhere else.
While you're at it, why not check out some of our many other Worksheet Sunday entries?