下面哪一项是传输层的协议数据单元（PDU）（） A.帧 B.段 C.数据包 D.比特
题型：单项选择题
问题：
下面哪一项是传输层的协议数据单元（PDU）（）
A.帧
B.段
C.数据包
D.比特
题型：单项选择题
Japanese students work very hard but many are unhappy．They feel heavy pressures from their parents to do well in school．Most students are always being told by their parents to study harder so that they can have a wonderful life．Though this may be good ideas for those very bright students，it can have very bad results for many students who are not quick enough at learning．
Unfortunately，a number of students killed themselves．Others are after co
mfort in using drugs．Some do bad things with trouble-makers and turn to crime．Many of them have tried very hard 
at school but have failed in the exams and have disappointed their parents．Such students feel that they are less important and leave school before they have finished their study．
It is surprising that though most Japanese parents are worried about their children, they do not help them in any way．Many parents feel that they are not able to help their children and that it is the teachers' work to help their children．To make matters worse, a lot of parents send their children to special school called juku-cram schools．These schools are open during the evening and on weekends, and their only purpose is to prepare students to pass exams, they do not try to educate students in any real sense of the real world. It thus comes as a shock to realize that almost three quarters of the junior or high school population attend these cram schools．
Ordinary Japanese schools usually have rules about everything from the students' hair to their clothes and things in their school bag．Child psychologists now think that such strict rules often lead to a feeling of being unsafe and being unable to fit into society．They regard the rules as being harmful to the development of each student．They believe that no sense of moral values is developed and that students are gi
ven neither guidance nor training in becoming good citizens．
小题1:A lot of Japanese students are unhappy at school because
A．they work very hard
B．they find they can't do well at school
C．they feel unimportant
D．they are under too much pressure小题2:Because of their failure at school, some students take drugs to
A．kill themselves
B．seek comfort
C．disappoint their parents
D．make trouble小题3:What should be the best title of the passage?
A．Students' Pressure
B．Students' Problems
C．The Negative Impact(影响) of Japanese Education
D．The Trouble in Japanese Schools小题4:In juku-cram schools students ．
A．are taken good care of by the teachers
B．feel no pressure
C．are trained to pass exams
D．can learn a lot of useful things小题5:In ordinary Japanese schools， ．
A．there are strict rules
B．students feel safe
C．students can do anything
D．learning is not important