（）是视频点播（VOD）系统的核心，它充分利用实时技术向客户端传输数字视频节目。

SECTION A COMPOSITION （35MIN）Nowadays，many universities are asking their students to evaluate their teachers.Many students are excited at this，but most teachers seem to hold different opinions.What’s your opinion？Write on ANSWER SHEET TWO a composition of about 200words on the following topic：Should Teachers Be Evaluated by Students？You are to write in three parts.In the first part，state specifically what your idea is.In the second part，provide one or two reasons to support your idea or describe your idea.In the last part，bring what you have written to a natural conclusion or a summary.Marks will be awarded for content，organization，grammar and appropriateness.Failure to follow the instructions may result in a loss of marks. 点击查看答案

OSI参考模型中定义了很多层次，各个层次之间的数据交换是通过（）来实现的。

A.API
B.buffer
C.SAP
D.RPC

点击查看答案&解析