题目内容：

    Some people may sneeze after touching a cute dog. Others may find it hard to breathe after eating a certain food. Why does this happen? That’s because they have allergies (过敏).

When a person is allergic to something, his or her immune system (免疫系统) mistakenly believes that this thing is harming the body. Some allergies may cause uncomfortable eyes or sneezing. Others may even make people stop breathing.

But why do people have allergies?

It can be because of their genes, which control what they look like, how they grow and how they develop.

You may be at risk for developing allergies yourself at some point in your life if one of your parents has eczema (湿疹) or food allergies, and they may develop in a certain order, Ogden told Gizmodo, a US technology and science website. A person may first have eczema in his or her childhood, and later see it develop into a food allergy.

But not all allergies are caused by genes. Some experts say that if we experience fewer infections (感染) when we are young, we are more likely to have allergies when we grow up.

According to Matthew Greenhawt from the University of Colorado, our immune system deals with infections and allergies. It tries to keep a balance between the two. But modern medicine protects us from developing various infections. This breaks the balance. Our immune system becomes more easily affected by allergies. It may think that normal things, such as certain foods, are dangerous and will try to protect us with an immune response.

根据材料内容选择最佳答案。

1.People who have allergies may ________ according to the text.

A.be likely to have cancer B.find it hard to fall asleep

C.have uncomfortable eyes D.have a cold easily

2.What does the underlined word “they” refer to?

A.Allergies. B.Parents. C.Genes. D.Points in life.

3.Which can make us more likely to have allergies when we grow up?

A.Not taking exercise. B.Eating unhealthy food.

C.Not having allergies before. D.Experiencing fewer infections.

4.Which of the following is TRUE according to the text?

A.Few people are allergic to animals.

B.Parents can’t pass allergies on to their children.

C.People may stop breathing when they have allergies.

D.Modern medicine has no influence on our immune system.

5.What does the text mainly talk about?

A.How to treat allergies. B.Why people have allergies.

C.When people may have allergies easily. D.What people have done with allergies.