Comprehension-based Instruction: the Foundation, the Method, the Evidence #ACTFL15 10 januari 2016 | Alike Last Comprehension-based Instruction: the Foundation, the Method, the Evidence. A video in three parts of Dr. Stephen Krashen’s and Carol Gaab’s session at the ACTFL Conference in San Diego, CA, Nov. 20-22, 2015. Video part 1 from Krashen-Gaab’s session at ACTFL 15 Video part 2: The History of Instruction: From Drills to Personalized Input Video part 3 from Krashen-Gaab’s session at ACTFL 15.