There are many reasons why you may need to use warm ups and time fillers while working as an English teacher:-to focus or bring energy to each class in the first ten to fifteen minutes -to break the ice with a new class of students -to fill a small block of time when a lesson runs shorter than you planned -to replace a lesson that students can't grasp or are bored with -to have on hand for emergencies such as broken audio-visual equipment or photocopiers -to use if you get called in last-minute to fill in for another teacher.