问题 问答题 简答题

疏水阀的分类及它的作用是什么?

答案

参考答案:

(1)机械型疏水器;

(2)热力型疏水器;

(3)恒温型疏水器。

作用:自动阻止蒸汽遗漏而且迅速地排出用热设备及管道中的凝结水,同时能排除系统中积留的空气和其它不凝性气体。

单项选择题

阅读理解:请根据短文内容,为每题确定l个最佳选项。

A New Strategy to Overcome Breast Cancer。

Post-menopausal(绝经后)women who walk for an hour a day can cut their chance of breast cancer significantly,a study has suggested. The report, which followed 73,000 women for 17 years,found walking for at least seven hours a week lowered the risk of the disease.The American Cancer Society team said this was the first time reduced risk was specifically linked to walking. UK experts said it was more evidence that lifestyle influenced cancer risk.

A recent poll for the charity Ramblers a quarter of adults walk for no more than an hour a week,but being active is known to reduce the risk of a number of cancers.This study, published in Cancer Epidemiology,Biomarkers&Prevention,followed 73.615 women out of 97,785 aged 50-74 who had been recruited by the American Cancer Society between 1992 and 1993,so it could monitor the incidence of cancer in the group.

They were asked to complete questionnaires on their health and on how much time they were active and participating in activities such as walking,swimming and aerobics(有氧运动)and how much time they spent sitting watching television or reading.They completed the same questionnaires at two-year intervals between 1997 and 2009. Of the women,47% said walking was their only recreational activity.Those who walked for at least seven hours per week had a 14% lower risk of breast cancer compared to those who walked three or fewer hours per week.

Dr. Alpa Patel, a senior epidemiologist at the American Cancer Society in Atlanta, Georgia, who led the study, said:”Given that more than 60% of women report some daily walking, promoting walking as a healthy leisure-time activity could be an effective strategy for increasing physical activity amongst post-menopausal women.We were pleased to find that without any other recreational activity, just walking one hour a day was associated with a lower risk of breast cancer in these women.””More strenuous(紧张的)and longer activities lowered the risk even more.”

Baroness Delyth Morgan, chief executive of Breast Cancer Campaign,said:”This study adds further evidence that our lifestyle choices can play a part in influencing the risk of breast cancer and even small changes incorporate into our normal day-to-day activity can make a difference.”

She added:”We know that the best weapon to overcoming breast cancer is the ability to stop it occurring in the first place. The challenge now is how we turn these findings into action and identify other sustainable lifestyle changes that will help us prevent breast cancer.”

All of the following factors relating to cancer risk were mentioned in the EXCEPT________.

A.breathing exercise

B.regular walking

C.recreational activity

D.lifestyle choices

阅读理解

I came to live here where I am now between Wounded Knee Greek and Grass Greek. Others came too, and we made these little grey houses of logs that you see, and they are square, It is a bad way to live, for there can be no power in a square.

You have noticed that everything an Indian does is in a circle, and that is because the Power of the World always works in circles, and everything tries to be round. In the old days when we were a strong and happy people, all our power came to us from the respectful circle of the nation, and so long as the circle was unbroken, the people were getting rich. The flowering tree was the living center of the circle, and the circle of the four quarters nursed it. The east gave peace and light, the south gave warmth, the west gave rain, and the north with its cold and strong wind gave strength and continuous power. This knowledge came to us from the outer world with our brief. Everything the Power of the World does is done in a circle. The sky is round, and I have heard that the earth is round like a ball, and so are all the stars. Birds make their nests in circle, for theirs are the same as ours. The sun comes forth and goes down again in a circle. The moon does the same, and both are round. Even the seasons form a great circle in their changing, and always come back again to where they were. The life of a man is a circle from childhood to childhood, and so it is in everything where power moves. Our places were like the nests of birds, and these were always set in a circle, the nation’s circle, a nest of many nests, where the Great Spirit meant for us to nurse our children.

But the Wasichus (Indian word for “white people”) have put us in these square boxes. Our power is gone and we are dying, for the power is not in us any more. You can look at our boys and see how it is with us. Where we were living by the power of the circle in the way we should, boys were men at twelve or thirteen years of age. But now it takes them very much longer to be bull - grown.

小题1: According to the passage, the Indians _______.

A.don’t have modern instruments in their homes

B.refused to move from round places

C.lived in round places, but were forced to live in square houses

D.lived in round places, but then decided to move into square houses小题2:Two things being compared in the passage are _______.

A.the Indians’ past and present living conditions

B.the Indians’ past and modern beliefs

C.the Indians’ old and new power

D.people and nature小题3:In the second paragraph “the four quarters” refers to _______.

A.the four rooms of the Indian’s house

B.the four kinds of natural power

C.the four seasons

D.the four directions小题4:According to the author, once the Indians moved into square houses, _______.

A.they had to move to other houses

B.boys took more time to grow into men

C.they forgot the old way of life

D.everyone was not happy