电信系统的基本组成包括（）、（）、信道、噪声源、反变换器及信宿。

已知某高中高一800名学生某次考试的数学成绩，现在想知道不低于120分，90～

120分，75～90分，60～75分，60分以下的学生分别占多少，需要做的工作是(  )

A．抽取样本，据样本估计总体

B．求平均成绩

C．进行频率分布

D．计算方差

Napoleon Bonaparte died on May 5, 1821, on the island of St. Helena off the coast of Africa. He was 51 years old at the time. When doctors examined Napoleon’s body, they said that the former emperor of France had died from cancer of the stomach. That was the cause of death recorded in the official report. However, other doctors disagreed. One doctor who was present during the examination of the body said that Napoleon died of hepatitis. Other historians and medical experts have suggested that Napoleon died of syphilis, tuberculosis, or perhaps malaria. Now, after careful research, a British chemist thinks that Napoleon might have been poisoned -- not by a person, but by his wallpaper.

Napoleon was sent to the island of St. Helena in 1815 after he lost the battle of Waterloo. He was a prisoner on the island. Although he had servants to attend to him, he had to live in one small building. St. Helena is a very wet island, so the walls of the building were always covered with mold. Napoleon became ill from spending too much time inside his house. Almost constantly he had a fever, chills, and felt sick to his stomach. He often felt pain in his shoulders and in his side. His skin turned yellow. He got frequent headaches, and he would become dizzy and vomit(吐). None of the medicine that the doctors gave Napoleon seemed to help. They were not sure what was the matter. Finally, Napoleon was too weak to leave the house. One night, while he was sleeping, he went into a coma and died.

Many doctors who later reviewed the reports of Napoleon’s illness found that the symptoms(症状) did not show a man who suffered from stomach cancer. It seemed obvious that Napoleon had died from some other cause. In 1961, a Swedish doctor examined some of Napoleon’s hair and found a high level of arsenic, a chemical poison. Was Napoleon murdered? It is doubtful. Arsenic was used in many types of medicine during Napoleon’s time, so he might have taken the arsenic as a cure for his illness. Then, in 1982, Dr. David Jones from England began to look into the mystery and suggested that Napoleon might have breathed in arsenic which was in the air of his house. In the 1700s and 1800s, arsenic was used to make a kind of green paint used on cloth and wallpaper. If the paint was used on a wet wall, the arsenic would go into the air. A person in the room might breathe that air. After studying the wallpaper in the room where Napoleon died, Dr. Jones found high levels of arsenic in the green paint on the walls.

小题1:Why did Napoleon live on St. Helena?

A．He owned the island.

B．He was a prisoner there.

C．His family lived there.

D．He liked the island.小题2:The official report said that Napoleon died of____________.

A．cancer

B．a coma

C． mold

D．poison小题3:Napoleon suffered from the following symptoms except __________.

A. chills      B. fever      C  dizziness     D. bleeding

小题4:According to Dr. Jones, how did the arsenic probably get into Napoleon’s body?

A．He drank it..

B．He touched it.

C．He breathed it in.

D．He ate it小题5:The passage says that                      .

A．a British doctor thinks he has found the cause of Napoleon’s death

B．many doctors have tried to guess the cause of Napoleon's death

C．Napoleon could have died from poison

D．all of the above

放在重要工作岗位上压担子不是党政管理干部接受培训的一种形式。( )

胆汁淤积型肝炎的诊断下列哪项是错误的（）

A．起病类似急性黄疸型肝炎

B．黄疸较深，消化道和全身症状相对较轻

C．常有皮肤瘙痒、明显肝肿大、大便颜色变浅

D．总胆红素明显升高，以间接胆红素为主

E．碱性磷酸酶(ALP)明显升高

双代号网络图的基本符号中，“箭线”表示( )。

A．工作名称
B．一项工作
C．工作持续时间
D．紧邻工作之间的逻辑关系