题目内容：

Nobody likes doing the dishes, but it turns out that doing this daily 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.

Researchers in Sweden surveyed the parents of 1,029 children ages 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 off slightly dirtier plates be better off when we talk about preventing allergies? One explanation is based on a theory known as the “hygiene hypothesis (卫生假说),” which says the reason why kids develop allergies is that their surroundings are actually too clean.

Your immune (免疫) system keeps you healthy by fighting germs (病菌) like bacteria and viruses. But when you have allergies, it overreacts and tries to fight ordinary things like pollen (花粉) or certain foods.

Being exposed to germs, particularly 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 excite 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.What’s the advantage of washing dishes by hand?

A. Hand-washed dishes are much cleaner.

B. It encourages people to do housework.

C. It helps prevent allergies.

D. Dishes are easier to wash.

2.What can we know about the theory of the “hygiene hypothesis”?

A. There is no harm done if kids live in a slightly dirty place.

B. There is no need to keep the surroundings clean.

C. It’s better for kids to use clean plates to keep healthy.

D. It’s wise to use a dishwasher to prevent allergies.

3.What does the underlined word “it” in Paragraph 4 refer to?

A. Pollen.    B. The immune system.

C. The germ.    D. A certain food.

4.What’s the result when our immune system becomes tolerant?

A. It’ll overreact to the foods we eat.

B. It’ll lead to the development of allergies.

C. It’ll make germs in our body more active.

D. It’ll prevent allergies and keep us healthy.