and their fourth foreign language by 10th grade. By 10th grade, students also choose if they want to drop one of the languages they started in 5th grade. Later, they may drop another language. Students are required to take at least two foreign languages and fluency is a requirement for graduation. If they wish, students may also graduate with four foreign languages. Gymnasium for mature students There are a number of gymnasia for mature students, people who graduated from school, but did not receive an Abitur. Most of these schools have only the top three or four year groups, rather than the traditional 5th to 13th years. Examples are the Abendgymnasium, the Aufbaugymnasium and the Wirtschaftsgymnasium. Culture of Teaching and Testing German gymnasia follow different pedagogical philosophies, and teaching methods may vary. In the most traditional schools, students rise when the teacher enters the classroom. The teacher says "Good morning, class" and the class answers "Good morning, Mr./Ms. ... ." The teacher then asks them to sit down. Up to the 1960s, students used to be supposed to call their teachers by the appropriate title, e. g. "Herr Studienrat." This is generally outdated. The headmaster might also be addressed more laxly as Herr Direktor (the correct title being Herr Oberstudiendirektor). The general mode of address is these days Mr. + surname. Teachers mostly address students by their first name. Corporal punishment was banned in 1973. Teachers who want to punish students put them in detention or assign them boring tasks. Some have them write essays like "Why a student should not interrupt his teachers." Students may also be subjected to official disciplinary measures, such as a Verweis (reprimand), not unlike equally-called measures in the disciplining of civil-servants or soldiers; the hardest of these measures is expelling from school. Such pupils have to go to another school, or even be banned from attending state schools altogether. This is rare though. Some private schools are more easy with expulsions, along with the line that the pupil in question does not fit into the community and should thus try his fortune with a school officially designated to take all pupils, i.e. a state school. There are written, as well as oral, exams. Written exams are essay-based and called Klausur and typically take one and a half hours. Many German students never take a multiple choice test. Gymnasium and academic grading Gymnasium is a