问题 单项选择题

GigabitEthernet为了保证在传输速率提高到1 000Mbit/s时不影响MAC子层,定义了一个新的______。

A.千兆介质专用接口

B.千兆单模光纤接口

C.千兆逻辑链路子层接口

D.千兆多模光纤接口

答案

参考答案:A

解析: 1000BASE-T标准采用了千兆介质专用接口(GMII),它将 MAC子层与物理层分割开来,这样物理层在实现1000 Mbit/s速率时所使用的传输介质和信号编码方式的变化不会影响MAC子层。

填空题

根据短文内容及首字母提示完成短文。

     Usually, doctors tell some people to go on  diets( 节食).  The doctors hope the diets will make the

people feel b    l    . They hope the diets will make the people healthy.

     Alana was on a diet, but she didn't like it at all. She wasn't a    2    to eat her favorite food by the

doctor. While her brother Frank ate chocolate, she had to eat an apple. Alana was on the diet for two

months. Her doctor was pleased with her. "You have been very good," he said.“You can eat some of

the food you like best but only a little. Don't eat too many sweets. Don't eat too much ice-cream.  If you

do, you will get a lot of weight a    3    . "

     Then the doctor put Frank on a diet. It was a different kind of diet. “You c    4    eat chicken or eggs,

Frank," said the doctor. "They will make you in trouble. "

     "How long will I have to be on the diet?" asked Frank.

     "A long time,” said the doctor.  “Maybe for the r    5    of your life. "

     "But I really  like  chicken,"  said  Frank.

     " You said it is one of the best meat to eat. "

     "It is very good food for most people," said the doctor.  "But when you eat it, it will make you sick. It

is not good food for you. "

          "You're right,"  said Frank.  "Well, I’ll eat more cake instead."

    1.            2.             3.             4.             5.             

判断题