If your class is using the Adventist quarterly then you can find an online version on the Sabbath School Net site. click on the image of the quarterly on the left side and it will give you the option of selecting the format that will work best for your device.
For those who wish to search the writings of Ellen G. White the estate has setup this site. (egwwritings.org)
If you are experiencing a slower connection you may with to use this simpler text interface (text.egwwritings.org).
The mobile devices version is m.egwwritings.org