What is the "R" for after levels 3.5, 4.5, and 7.0?
These three levels were revised from their original versions. In 1999, a number of the stories in levels 3.5 and 4.5 were either modified or replaced.
In 2004, the planet stories in level 7.0 were replaced with new stories. The revised level 7.0 also features paired stories and additional comparison questions.
Teachers with the older blackline masters and cassettes or audio CDs for these three levels need to know that they cannot use the current materials with the earlier ones.