2 when peter was teaching in a high school in vietnam , he often felt frustrated .
his students worked hard and did well in their tests .
but during class , they never spoke .
peter thought that they didn't like him ! one day , peter told another teacher
about his problem . the teacher told him that in vietnam , it is very rude for
students to speak in class . they are expected to listen to their teachers and
write down everything they say . they are not usually asked what they think .