Every flu season it seems like we’re bombarded (炮轰, 轰击) with commercials for new and improved medicines promising to relieve terrible headaches and f___1___. But for many people around the world, the secret to avoiding a nasty or even fatal cold might lie in a better diet, not drugs. Researchers from the University of North Carolina at Chapel Hill, the Beltsville Human Nutrition Research Center in Maryland, and the Nestle Research Center in Switzerland have found that a deficiency of the mineral selenium (硒) may c___2___ to the spread of highly virulent strains of influenza virus.

The team infected two g___3____ of mice—one that had sufficient selenium in their diets and one that did not — with a type of flu that also affects h___4___. The selenium-deficient mice were more l___5___ to get sick after being infected. More worrisome (令人不安的), the flu virus grew m___6___ virulent when it re-emerged for the selenium-deficient mice.

Random mutations (变异) normally alter the genes responsible f___7___ designing the proteins on the virus’s surface. But in selenium-deficient mice, “it’s the exact opposite to what we expected,” says Beck, a researcher. The rapid mutation was instead occurring in genes that code for internal proteins. Those changes, she says, might reprogram the flu strain, making it more contagious (传染性的).

Beck and her team are still uncertain exactly h___8___ selenium fits into the puzzle, but scientists know the mineral is necessary for antioxidant (抗氧化剂) activity in the body. without selenium, excess (过度的) free radicals wreak havoc (发泄, 报仇) on the viral (滤过性病毒) RNA, leading to those unexpected mutations, says Beck.

Common sources of selenium include breads, meats and fish, foods that Americans eat in abundance, says Orville Levander, a chemist at the Beltsville Nutrition Center. But Levander points out that some areas in China l___9___ selenium in the soil, and people who live there require selenium supplements to a___10___ health problems.

答案

 1. fever     2. contribute          3. groups        4. humans     5. likely

 6. more     7. for                 8. how       9. lack            10. avoid