题干

下列各组混合物中,不论两种物质以何种比例混合,只要总质量一定,经过完全燃烧后,产生的CO2质量不变的是(  )

A:乙炔和甲苯

B:丙烯和丙烷

C:乙醇和丙酸

D:甲醛与葡萄糖

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D

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    The book ABigFatCrisis: TheHiddenForcesBehindObesityEpidemicandHowWeCanEndIt by Deborah Cohen, a senior natural scientist, is very popular now. ____ But according to this book, the following are some misunderstandings of obesity or being overweight.

1).If you're obese, blame your genes.

    ____ Yet, between 1980 and 2000, the number of Americans who are obese has doubled—too quickly for genetic factors to be responsible. At restaurants, a dollar puts more calories on our plates than ever before, because restaurant meals usually have more calories than what we prepare at home, so people who eat out more frequently have higher rates of obesity than those who eat out less.

2).If you're obese, you lack self­control.

    Research shows that if we are faced with too much information, we have a tendency to make poor choices on diet. ____ Even, the most vigilant(警觉的)people may not be good controllers of themselves.

3).____

    Although the US Department of Agriculture estimates that fewer than 5 per cent of Americans live in the “food deserts”, about 65 per cent of the nation's population is obese. For most of us, obesity is not related to access to more fresh fruits and vegetables, but to the choices we make in supermarkets.

4).The problem is not that we eat too much, but that we don't exercise.

    Michelle Obama's “Let's Move” campaign is based on the idea that if kids exercise more, childhood obesity rates will decrease. ____ In fact, although a drop in work­related physical activity may explain up to 100 fewer calories burned, leisure physical activity appears to have increased.

A.Lack of access to fresh fruits and vegetables is a cause of obesity.

B.Obesity rates have increased.

C.Fresh fruits and vegetables we choose in a supermarket are related to obesity.

D.But there was no obvious decrease in physical activity levels as obesity rates climbed in the 1980s and 1990s.

E.People hold different views on obesity.

F.People benefit a lot from physical activities.

G.Our world has become so rich in food that we can be led to consume too much in ways we can't understand.