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问题 选择题

经测定，某工厂排放废水的pH为3，会污染环境．若将该废水治理，使pH变为8，可向该水中加入适量的（　　）

A．氯化钠

B．硫酸

C．氧化钙

D．废铜片

答案

酸性溶液要想变成碱性的必须加入碱性物质，且要过量．

A、氯化钠溶液呈中性，加入氯化钠后溶液的pH＜7．

B、硫酸显酸性，加入硫酸后溶液的pH＜7．

C、氧化钙和酸性物质反应生成盐和水，和水反应生成氢氧化钙，氢氧化钙的水溶液显碱性．

D、铜和pH为3的溶液不反应．

故选C

单项选择题

涵洞类型不是按其结构形式分的是（）。

A、圆涵

B、箱涵

C、拱涵

D、石涵
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填空题

Less education, income linked to obesity in women, not men


Women who are better educated and live in households that are middle-income or above are less likely to be obese than women who are less educated and live in the lowest income households, new government research shows.
Among men, there is not a statistically significant (26) in obesity based on income and very (27) difference based on education, the data show.
(28) , about one in three U.S. adults-almost 73 million people-are obese, which is (29) 30 or more pounds over a (30) weight. Extra weight raises the (31) of diabetes, heart disease, some types of cancer and other (32) .
"There is a relationship between obesity and income, but it’s not a (33) story," says Cynthia Ogden, an epidemiologist with the National Center for Health Statistics, part of the Centers for Disease Control and Prevention.
"When looking at these two (34) of socioeconomic status-income and education-their (35) is greater on women than men," she says.
Jennifer Lovejoy, president of the Obesity Society, says that (36) -income women may be more likely to become obese because of environmental (37) such as lack of access to safe places to do physical activity and easy access to fast food.
Among the findings:
·29% of women who live in households with an annual income of $77,000 or more for a family of four are obese in opposition (38) 42% of women who live in households with an annual income below $29,000 for a family of four.
·23% of women with a college degree are obese, significantly less than the 42% of women with (39) than a high school education.
·33% of men who live in households with an annual income of $77,000 or more for a family of four are obese, (40) 29% of men who live in households with an annual income below $29,000 for a family of four are obese. This difference is not considered statistically (41) .
The analysis is based on (42) from the National Health and Nutrition Examination Survey, which is considered the gold (43) for evaluating obesity because it is a(an) (44) survey of people whose weight and height are actually (45) rather than being self-reported.

A. states B. members C. records D. measures
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