Generally, price and demand is _______ related which means that the increase in the price would lead to the decrease in the demand for that product and vice versa. A: inversely B: adversely C: correspondingly D: proportionally

重心随着机翼上的载荷而移动。 A: The center of gravity moves in relation to the loads on the wings. B: Movement of the center of gravity is proportional to the loads on the wings. C: Movement of the center of gravity is proportionally the loads on the wings.

重心随着机翼上的载荷而移动。 A: The center of gravity moves in relation to the loads on the wings. B: Movement of the center of gravity is proportional to the loads on the wings. C: Movement of the center of gravity is proportionally the loads on the wings.

重心随着机翼上的载荷而移动。 A: The center of gravity moves in relation to the loads on the wings. B: Movement of the center of gravity is proportional to the loads on the wings. C: Movement of the center of gravity is proportionally the loads on the wings.

重心随着机翼上的载荷而移动。 A: The center of gravity moves in relation to the loads on the wings. B: Movement of the center of gravity is proportional to the loads on the wings. C: Movement of the center of gravity is proportionally the loads on the wings.

The AS-curve is horizontal or very flat if A: additional resources (especially labor) can be hired to produce additional output with little or no increase in existing prices B: wages fall rapidly with an increase in unemployment, reducing spending and income to restore equilibrium C: firms lower wages less than prices to avoid a loss in profit during a recession D: the nominal wage adjustment occurs fairly rapidly E: nominal wages and prices always change proportionally, leaving the real wage rate unchanged

Why do smokers tend to weigh less than nonsmokers and gain weight when they give up the habit? Contrary to “common knowledge”, nonsmokers do not generally eat more than smokers, nor do they exercise less, studies find. Research performed on smokers at rest indicates that nicotine (尼古丁) itself can increase basal metabolic (新陈代谢的) rates, meaning smokers burn more energy than nonsmokers during periods of inactivity. But surveys suggest most smokers smoke not while completely at rest, but while performing light activities such as desk work that can increase metabolic rates by two or three times. Unless nicotine’s metabolic effects increase proportionally with metabolic rates, its influence on weight might be insignificant. Now a study shows that nicotine’s effects on body-fuel consumption indeed increase proportionally with increases in activity. “These results indicate that the metabolic effect of nicotine may play a greater part in accounting for body-weight differences between smokers and nonsmokers than was previously believed,” says Kenneth A. Perkins and his colleagues at the University of Pittsburgh School of Medicine. The researchers gave a nicotine nose spray to individuals performing light work — in this case riding an exercise bicycle modified to allow easy riding while subjects remain seated in a comfortable armchair. The activity raised resting metabolic rates two to three times. By analyzing air breathed out, the researchers calculated energy consumption in the armchair bicyclists before and after giving the nose spray and compared the relative changes with subjects in the control group given placebo (（试验药物用的）无效对照剂) nose sprays. Relative to their baseline bicycle expenditures, individuals in the nicotine group expended considerably more energy than did those in control group while doing the same amount of work. With nicotine, Perkins says, “It’s as if the body is becoming much less efficient in using its stored energy.” While the results may seem discouraging to smokers who’d like to quit without gaining weight, Perkins notes that walking an extra mile a day should make up for the difference in metabolic efficiency. And he says smokers would have to gain “well more than 50 pounds” to counterbalance the health risks of continued smoking.