问题 单项选择题

TCP是一个面向连接的协议,为了提高效率,又引入了滑动窗口协议,协议规定重传的分组是( )。

A.未被确认

B.仅丢失的

C.未被确认及至窗口首端的所有分组

D.未被确认及至退回N值的所有分组

答案

参考答案:A

解析: 在TCP中最重要的思想之一在于处理超时与重传的机制。TCP每次发送一个报文段,都启动一个计时器并等待确认。如果数据流中的数据发出后尚未得到确认,计时器已经计时完毕,TCP便假定这个报文段已经丢失或遭到破坏,因此重传这个报文段。

阅读理解

阅读短文,按要求完成各题。

If the eyes are the windows of the soul, then the body is the mirror of our feelings. If we are feeling great, we may give our body signals(信号). If we look at someone else’s body, we can often tell how thy are feeling by their body signals. So reading body language signals is a great tool in daily communication.

In case(假使) you don’t think that learning how to read and use body language is important, here are some numbers for you. 7% of the information we receive is from what people actually say, and 38% of the information we receive is from the tone(语气) and the speed of their voice; while 55% of the information we receive is from their body language.

These non-verbal(非语言的) signals will help you a lot, but you still need to focus on what people are saying. If you focus too much on their body language signals, you and the person may feel uncomfortable. It is useful to be able to read people’s body language, but it is useful to learn how to send the right signals and avoid the wrong signals too. Body language may be given several interpretations. Many signals have different meanings, depending on the person and the situation. Be sure of it when you are trying to read a body language signal.

Facial expression is one of the body languages. Facial expressions are one or more movements on a person’s face, such as frowning(皱眉),raising your eyebrows and rolling(旋转) your eyes. Scientists say that humans have 80 muscles(肌肉) on their faces. These muscles can make 7.000 different facial expressions. These expressions can be put into six classes. They are happiness, sadness, anger, surprise, fear and disgust(厌恶)。

For example, when people think a certain food tastes disgusting, they usually make a funny face. When people are surprised, they often raise their eyebrows and open their eyes wide.

If people can read facial expressions correctly, they may be better at knowing other people’s feelings. That can help people make more friends. However, sometimes people have to be careful when reading others’ faces. It’s rude to stare at others for a long time.

小题1:根据短文内容完成句子(每空限填一个单词)。

From the first paragraph of the passage, we know that          your eyes         your body language signals are great tools in daily communication.

小题2:根据短文内容完成句子(每空限填一个单词)。

From the second paragraph of the passage, the numbers mentioned are to show the       

         body language.

小题3:根据短文回答问题。

According to the passage, how many classes of facial expressions do you know? What are they?                       

                                                                       

小题4:把短文中画底线的句子译成汉语。

                                                                        

小题5:根据短文内容用一个完整的英文句子(限10词以内)回答问题。

What is the writer’s opinion on the body language?

                                                                       

问答题 简答题