Watching a child struggle to breathe during an asthma(哮喘) attack is frightening for any parent. So it is only natural that most moms and dads will try just about anything — including spending a lot of money — to keep an attack at 41 . Trouble is, more than half of parents are trying strategies that simply don't work and wasting hundreds of dollars in the 42 . According to Dr. Michael Cabana, a pediatrician at the University of Michigan's C.S. Mott Children's Hospital, who led the study, one of the most 43 mistakes was to buy a mattress cover to protect against dust mites(尘螨) for a child whose asthma instead was made even worse by plant pollen. Many of those parents then 44 to do what would have helped a lot more: shut the windows to keep pollen out. Another was using a humidifier for a child who was allergic(过敏) to dust mites; a humidifier 45 to be a place where dust mites like to 46 . With those allergies, a dehumidifier works better. Worst of all was the number of smokers with asthmatic children who didn't even try to quit or at least 47 themselves to smoking outdoors rather than just moving to another room or the garage. Many smoking parents 48 expensive air filters that have what Cabana called "questionable utility." Part of the problem, Dr. Cabana and his colleagues believe, is that parents are bombarded by television ads that encourage them to buy products such as air and carpet fresheners, ionizers and other remedies that are often expensive but medically 49 . And doctors may not always take the time, or have the time, to explain to parents what will and won't work in their child’s particular case. 1. 41 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected 2. 42 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected 3. 43 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected 4. 44 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected 5. 45 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected 6. 46 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected 7. 47 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected 8. 48 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected 9. 49 A: breed B: common C: limit D: spends E: process F: purchased G: tends H: bay I: unnecessary J: neglected