下列说法正确的是（    ）

阅读理解

    A new study suggests that washing dishes by hand is healthier than using a dishwasher.

    Nobody likes doing the dishes, but it turns out that doing this task might pay off in an unexpected way. According to a new study published in the Journal of Pediatrics, washing dishes by hand instead of using a dishwasher might prevent the development of allergies (过敏).

    Researchers in Sweden surveyed the parents of 1,029 children aged 7 and 8. They discovered that children whose families hand-washed the dishes instead of using a machine were less likely to have allergies.

    Earlier research has shown that dishes washed by machine are cleaner than those washed by hand. So why would kids who eat with slightly dirtier plates be better when it comes to preventing allergies? One explanation is based on a theory known as the “hygiene hypothesis,” which says the reason why kids develop allergies is that their environment is actually too clean. Your immune system keeps you healthy by fighting germs like viruses and bacteria. But when you have allergies, it overreacts and tries to fight ordinary things like pollen(花粉) or certain foods.

    Being exposed to germs, especially early in life is good training for the immune system, says the lead author of the study, Dr. Bill Hesselmar of Queen Silvia Hospital in Sweden. “You stimulate the immune system in various ways and it becomes tolerant.”

    This study shows that while using the dishwasher might be easier, the old-fashioned method of cleaning up could be better for your health.

①因一时冲动将他人打成重伤

②取得好成绩，我们有荣誉感

③“神舟十一号”发射成功，我们有自豪感

④犯了错误，我们有羞愧感