"It happens to even the best teachers: a well thought out, carefully planned lesson goes horribly wrong and you are stuck in the middle of class with confused, frustrated, and disengaged learners.
Students can react to material in different ways than you anticipated and new activities may take less time, be more challenging, or not work out quite the way you expected. Never continue following a lesson plan that is failing. This will only waste everyone’s time and students will not get the most out of their lesson with you. It is hard to think of new ideas and come up with an alternate plan during a lesson but this is the best course of action."
When Things Go Wrong: How to Turn a Disaster ESL Lesson into a Triumph
When Things Go Wrong: How to Turn a Disaster ESL Lesson into a Triumph: