In the United States, it is important to be on time , or punctual , for an appointment , a class, a meeting, etc. However, this may not be true in all countries. An American professor discovered the difference while teaching a class in a Brazilian  university. The two-hour class was scheduled to begin at 10 A.M. and end at 12. On the first day , when the professor arrived on time, no one was in the classroom. Many students came after 10:30 A.M. Two students came after 11 A.M. Although all the students greeted the professor as they arrived, few apologized for their lateness.Were these students being rude? He decided to study the students' behavior. The professor talked to American and Brazilian students about lateness in both an informal and a formal situation:at a lunch with a friend and in a university class, respectively.He gave them an example and asked them how they would react, If they had a lunch appointment with a friend,the average American student defined lateness as 19 minutes after the agreed time,On the other hand.the average Brazilian student felt the friend was late after 33 minutes. In an American university, students are expected to arrive at the appointed hour.In contrast, in Brazil,neither the teacher nor the students always arrive at the appointed hour.Classes not only begin at the scheduled time in the United States,but also end at the scheduled time.In the Brazilian class, only a few students left the class at 12:00;many remained past 12:30 to discuss the class and ask more questions.While arriving late may not be very important in Brazil , neither is staying late. The word'punctual'most probably means  _  .
1eaving soon after class coming early arriving a few minutes late being on time