It can be difficult to clearly distinguish between lessons and activities, because lessons typically include various activities. Additionally, because lessons vary in length-a lesson might last 30 minutes or 3 day- it can be tricky to determine when a lesson begins and when it ends, therefore, it is hard to know where an activity fits. However, our objective is not that teachers will be 100 percent accurate in distinguishing lessons from activities. Our belief is that being aware of the differences between the two will help teachers make good instructional decisions.