It’s a hot day and I am reliefing a three period class straight. If something bad happens then we’ d be responsible. In a class control, don’t give overambitious instructions. If they do not do what you say, then you would get angry. In 4E they have chosen their electives and when they have finished their school days they are going to practise what they are learning now. When it’s a 2 hour class, you can’t teach theory for three hours.