dialogue: W: What is the difference between a lesson and a lecture? M: Well, they are both ways of imparting knowledge, but the main difference is that you participate in a lesson whereas you just listen to a lecture. A lecture is generally given to a much larger group.
question: What does the man mean?
choice: A lesson requires students' active involvement. Students usually take an active part in a lecture. More knowledge is covered in a lecture.
answer: A lesson requires students' active involvement.