D
What's driving the rise of obesity in the United States? A group of economists argued in a recent study that big-box grocers, warehouse clubs and fast-food restaurants are key contributors to the county's obesity epidemic(流行病).
General economic factors, ranging from unemployment to income, as well as the financial
or time costs of eating and physical activity account for 43 percent of the rise in obesity, according to a recent study published by the US National Bureau of Economic Research, as the adult obesity rate in the United States has surged from 13 percent in 1960 to 35 percent in 2012.
"Supercenter/warehouse club expansion and increasing numbers of restaurants are the leading drivers of the results," the study concluded. "We show that supercenter/warehouse club density increases the probability of weight loss attempts, raising the possibility that cheap food from these retailers triggers self- control problems."
The study suggests that the rise of supercenters and warehouse clubs, like Walmart and Costco, may impact Americans' eating habits as they make calorie-rich food cheaper and more accessible, and save customers a lot of time.
"Food's gotten cheaper and more readily available, so we eat more of it. It's really simple," said Charles Courtemanche, co- author of the study and a health economist at Georgia State University, in an interview with National Public Radio (NPR). "At least a sizable portion of the rise in obesity can be characterized as response to economic incentives."
Obesity, defined as a body mass index (BMI) of at least 30, leads to adverse health conditions such as heart disease, diabetes, high blood pressures and stroke.
Obesity has become a major public health concern in the United States as the nation has one of the highest obesity rates in the world, according to the Organization for Economic Cooperation and Development (OECD).
What does the underlined word “trigger”mean?

A．Cause.	B．Raise.
C．Solve.	D．Explain.

From the passage we can infer _____.

A．the writer are opposed to fast-food restaurants .

B．43 percent of the Americans are overweight.

C．America people begin to be concerned about obesity problem.

D．calorie-rich food are becoming much more expensive.

As reasons for obesity , which of the following hasn’t been mentioned in the passage?

A．Unemployment.	B．Physical activity.
C．Eating time.	D．Genes.

What is the writer’s purpose to write this passage?

A．To do research into people’s eating habit.

B．To analyze the reasons for people’s becoming fat.

C．To tell people calorie-rich food is bad for health.

D．To introduce the boom of big-box grocers.

In which column of a newspaper can you find this passage?

A．Anecdote.	B．Life.
C．Business.	D．Science.