Complex sentence: Between 2001 and 2006, new tests were added so that beginning in spring 2006, all students in grades 3 through 8 and 10 participated in English Language Arts/Reading and Mathematics tests.
Split into simpler sentences: Between 2001 and 2006, new tests were added. Beginning in spring 2006, all students in grades 3 through 8 and 10 participated in English Language Arts/Reading and mathematics tests.