时分多路复用通信,是各路信号在同一信道上占有不同时间()进行通信。

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问题:

时分多路复用通信,是各路信号在同一信道上占有不同时间()进行通信。

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阅读理解。

     When he died in April of 1983, Dr. Joel Hildebrand was 101years old, who had been married for

seventy-five years,and had taught freshman chemistry to over 40,000 college students. For his life, he had

published a popular chemistry textbook and dozens of articles,had managed the U.S. Olympic ski team, and

discovered a way to allow deep-sea divers to stay underwater longer.In his own way,Dr. Hildebrand was

certainly a genius.

     Dr. Hildebrand's interest in chemistry began at an early age. In an interview, he once said that his interest

had to make his own decision about what to pay attention to.Even as a student in high school, Dr. Hildebrand

had the fame as the one who learned more chemistry than his teacher knew. As a result he was given the keys

to the high school chemistry lab, and there he discovered that the correct formula (公式) for a certain chemical compound was not the one given in his chemistry book but a totally different one. Dr. Hildebrand went on to

teach at the University of California at Berkeley and remained there for almost forty years.

     During that time, Dr, Hildebrand discovered that the gas helium (氦)could be combined with oxygen for use

as diving gas to allow divers to dive deeper and take the great pressure of the water without the physical

discomforts that had been experienced when that used another gas, nitrogen. The use of helium for deep-sea

diving is now standard practice.Dr. Hildebrand was also valuable to his country during both world wars. In

World War I he analyzed the poisonous gases used on the battlefield and helped develop a truck that could

clean and treat soldiers' clothes which had been contaminated (弄脏) by poisonous gases during fighting. In

World War II he helped develop a type of snowmobile,a vehicle used to carry the soldiers through the snow in

northern countries. Dr. Hildebrand's retirement (退休) from teaching at the age of seventy was required by

state law in California.

      He objected to this,joking he thought a teacher's time of retirement ought to be determined not by age but

by how many of that teacher's students were still awake after the first fifteen minutes of class!

     Dr. Hildebrand's writing career continued,however, and was still feeling strong at the age of 100,when he

published an article on the theory of chemical solutions. Dr. Hildebrand's love of life and his interest in it were

an inspirations to all who knew him. When asked once how he could have such ageless energy and vigor, he

said,"I chose my ancestors carefully."

1. In the eyes of Dr. Hildebrand,television was probably_____.

A.  powerful tool for knowledge learning.

B. A favourable means to encourage learning.

C. Something that was not helpful to people's attention

D. Something that man had to use in their daily life.

2. When Dr. Hildebrand was still a high school student, he was well known because ____.

A. he was good at chemistry.

B. Could use the chemistry as he liked.

C. His teachers were not so clever as he was.

D. Discovered the formula for some chemical compound(成分)

3. The use of helium in deep-sea diving ______.

A.  is now still regarded as standard practice for deep-sea diving.

B. was discovered with the help of Dr. Hildebrand's teachers.

C. was a great help to the invention of snowmobiles.

D. helped to make the divers love their job.

4. The best topic of the passage should be _____.

A. A Man Who Loved His country Deeply

B. A Well-know Professor of Chemistry

C. A Man Who Lived a Long and Valuable Life

D. The Greatest Discovery of the Century

题型:填空题

《环境空气质量标准》(GB3095-1996)中季平均值指任何一季的月平均浓度的算术均值。

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某村庄有一位德高望重的老人,他经常这样教育自己的子孙:“施恩图报非君子,恩将仇报是小人”“受人点滴之恩当以涌泉相报”“为人处事不可有贪心,衣能遮体,食能果腹,足矣”“得饶人处且饶人”“浪费会遭到报应”。你认为老人的言论反映出他继承了中国哪些传统思想?(   )

①儒家     ②道家      ③墨家    ④法家

A.①②

B.②③

C.①②③

D.①②③④

题型:填空题

临界区是指并发进程访问共享变量段的( )。

A.管理信息

B.信息存储

C.数据

D.代码程序

题型:填空题

训练实施是训练的基本阶段,是实现训练目的的主要过程。

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