Questions 47 to 56 are based on the following passage.
Just when you had figured out how to manage fat in your diet, researchers are now warning against another common mealtime pitfall (陷阱) - salt. A study by researchers at the University of California, San Francisco (UCSF), Standford University and Columbia University shows that even a __47__ decrease indaily salt intake (摄入) can lead to dramatic health benefits. The authors __48__ an annual drop of as many as 120 000 cases of heart disease, 66 000 __49__ of stroke and 99 000 heart attacks __50__ by high blood pressure after a 3-g-per-day reduction in salt. The advantages, not surprisingly, were greater for African Americans, who are more likely to __51__ high blood pressure than other ethnic groups, and for the elderly, since blood vessels stiffen with age, which can lead to higher blood pressure. "Everyone in the US is consuming salt far in __52__ of what is good for them," says lead author Dr. Kirsten Bibbins-Domingo of UCSF. "What we are suggesting is that a population-wide effort to reduce salt intake, even __53__ will have health benefits." The team conducted a computer-based analysis to determine the __54__ of a 3-g-per-day reduction in salt intake on rates of heart disease and death. They also calculated the cost savings emerging from the amount of disease that would be __55__ because of lower blood pressure. The conclusion: by cutting salt intake nationwide, the US could save $10 billion to $24 billion __56__ in health care costs.

48（）