From 1789 to 1850,these formative decades also brought _and _changes

A、to construct the model of experience

B、to construct the logic relations.

C、to construct grammar

D、to constract lexicon

A、To attend conferences

B、To keep up with new information

C、To stay current in the field and practice the science

D、All of the above

A、Upper duodenum

B、the descending part of the duodenum

C、the horizontal part of duodenum

D、the ascending part of the duodenum

A、the marginal product of labor in the production of cloth times the price of cloth.

B、the ratio of the marginal product of labor in the production of cloth to the marginal product of labor in the production of food times the ratio of the price of cloth to the price of food.

C、the slope of the production possibility frontier.

D、the average product of labor in the production of cloth times the price of cloth.

Over the past decade, many companies had perfected the art of creating automatic behaviors-habits-among consumers. These habits have helped companies earn billions of dollars when customers eat snacks or wipe counters almost without thinking, often in response to a carefully designed set of daily cues.

"There are fundamental public health problems, like dirty hands instead of a soap habit, that remain killers only because we can't figure out how to change people's habit," said Dr. Curtis, the director the Hygiene Center at the London School of Hygiene & Tropical Medicine. " We wanted to learn from private industry how to create new behaviors that happen automatically. "

The companies that Dr. Curtis turned to-Procter & Gamble, Colgate-Palmolive and Unilever-had invested hundreds of millions of dollars finding the subtle cues in consumers' lives that corporations could use to introduce new routines.

If you look hard enough, you'll find that many of the products we use every day-chewing gums, skin moisturizers, disinfecting wipes, air fresheners, water purifiers, health snacks, teeth whiteners, fabric softeners, vitamins are results of manufactured habits. A century ago, few people regularly brushed their teeth multiple times a day. Today, because of shrewd advertising and public health campaigns, many Americans habitually give their pearly whites a cavity- preventing scrub twice a day, often with Colgate, Crest or one of the other brands.

A few decades ago, many people didn't drink water outside of a meal. Then beverage companies started bottling the production of far-off springs, and now office workers unthinkingly sip bottled water all day long. Chewing gum, once bought primarily by adolescent boys, is now featured in commercials as a breath freshener and teeth cleanser for use after a meal. Skin moisturizers are advertised as part of morning beauty rituals, slipped in between hair brushing and putting on makeup.

"Our products succeed when they become part of daily or weekly patterns", said Carol Berning, a consumer psychologist who recently retired from Procter & Gamble, the company that sold $76 billion of Tide, Crest and other products last year. "Creating positive habit is a huge part of improving our consumers' lives, and it's essential to making new products commercially viable. "

Through experiments and observation, social scientists like Dr. Berning have learned that there is power in tying certain behaviors to habitual cues through ruthless advertising. As this new science of habit has emerged, controversies have erupted when the tactics have been used to sell questionable beauty creams or unhealthy foods.

According to Dr. Curtis, habits like hand washing with soap______.

A．should be further cultivated

B．should be changed gradually

C．are deeply rooted in history

D．arc basically private concern

Over the past decades, the population in this country____because of the rising birth rate, immigration and the declining death rate. A．has been increasing B．have been increasing C．had increased D．have increased

A、1793

B、1794

C、1795

D、1796