Teacher: Ok, tomorrow you are going to have a shorter day, since yesterday we were here until 6 pm. And make sure you do this exercise by the day after tomorrow since we are going to go through it then. Is this clear?
Students: Yes……… So may we go now?
Teacher: No, of course not. We will finish at four.
Student: Not at two o’clock?
Teacher: Today we will finish at four o’clock. So today is a normal day. Tomorrow we will finish at two o’clock because we had a longer day yesterday. Ok?
Students: And the exercise?
Teacher: The exercise has to be ready the day after tomorrow, which is Thursday.