问题 选择题

在生产和科学研究中,需要用到一些保护气。当焊接金属时,为了隔绝空气,能作为保护气的一组是( )

A.氧气、氩气

B.氮气、氧气

C.天然气、氧气

D.氮气、氩气

答案

答案:D

可用作保护气的气体必须是化学性

质不活泼的气体。氮气化学性质不活泼,在常温下难与其他物质发生反应,氩气是稀有气体,一般不跟其他物质发生反应,因此焊接金属时,为了隔绝空气,氮气、氩气可作为保护气。天然气能燃烧,氧气能支持燃烧,因此天然气、氧气不能用作为保护气。

阅读理解

Iceland has the highest birth rate in Europe, the highest divorce rate, and the highest percentage of women working outside the home. Such statistics are often evidence of a miserable, chaotic(混乱的)society, with loads of children, broken homes and absent mothers. But Iceland is the exception – its citizens are the happiest in the world.

Perhaps the country's geographic location contributes to Icelanders' happiness. Located in the middle of the North Atlantic, with Greenland as its nearest neighbor, Iceland is free from the taboos(禁忌)that cause so much trouble elsewhere. For instance, people who divorce are not looked down upon by society.

Icelanders are offsprings(后代)of the Vikings, a north European people who invaded European coasts from the 8th through the 10th century. This tradition of getting out into the world lives on in modern-day Iceland. Practically all Icelanders have studied or worked abroad, and most speak English.

Perhaps as a result, Iceland's economic policies blend the best of those from Europe with the US to create its own welfare system.

"Many of us have lived in the US, and studied there," said the Icelandic Prime Minister Geir Haarde. "We have both taken from them and found that naturally we share the can-do attitude—— that if you work hard, anything can be done."

Indeed, the country is rich in writers, painters, film makers and musicians. There's Sigur Ros, a post-rock band, and also a national symphony orchestra that plays to the highest standards all over the world. Half the population appears to have written a book.

"Iceland has harsh(恶劣的) nature, with its bitter ever-changing weather,” said Haraldur Jonsson, a painter, sculptor and video and performance artist. “We cannot escape it. So we find ways________. We have to have a rich internal(内在的)life to fill the empty spaces."

57.It is commonly believed that high birth rate and divorce rate will bring about ________.

A.social problems             B.happiness

C.a unique welfare system    D.modern way of life

58.The underlined word "blend" in the fourth paragraph means            .

A.combine      B.correct         C.compare      D.compete

59.Which of the following is NOT mentioned as the reason for Icelanders’ happiness?

A.Geographic location.       B.A rich internal life.

C.National pride.     D.Freedom from taboos.

60.The most suitable phrase to fill in the blank in the last paragraph is             .

A.to get rid of it   B.to have it changed  C.to get away from it       D.to live with it

问答题