四、阅读与回答问题
We all know teeth are important to our lives. So we celebrate National Love Teeth Day on 20 September.
Do you know the life cycle（生命周期）of teeth in your mouth? By age 3 or 4, most children have 20 baby teeth. From 6 to 13, people lose their baby teeth one by one. Now permanent teeth（恒牙）begin to grow. Between the ages of 17 and 25, some people grow wisdom teeth（智齿）. Of course, wisdom teeth don’t make you any smarter. They are seen as a symbol of growing up.
Do you know how to keep your teeth strong and healthy? There are some easy
ways. Let’s look at the following tips.
What we can do
Brush（刷）your teeth at least twice a day: in the morning and before bedtime. Brush for at least two or three minutes every time. Brush up and down on every tooth. Use dental floss（牙线）for your teeth to make them cleaner. Get a new toothbrush every three months.
What we can’t do
Don’t eat too much candy or sweet food. Don’t drink too much soda（苏打汽水）. Don’t eat very hard food. Don’t eat snacks before bedtime. They can hurt your teeth.
Teeth are important to everyone. Healthy teeth help us eat well and enjoy good food. They help us speak clearly. And yes, they help us look good.
1. When do we celebrate National Love Teeth Day?
On 20 September.
2. How many baby teeth do children under 6 years old have?
Twenty/20.
3. Why do we need to use dental floss?
To make our teeth cleaner.
4. How often should you get a new toothbrush?
Every three months.
5. How do you keep your teeth healthy in your daily life?（请自拟一句话作答）
I brush them twice a day./I don't eat too much candy.（言之有理即可）
解析：
【分析】本题为英语阅读理解的细节查找类题目，解题思路为：先通读全文把握文章主题（牙齿的生命周期及护牙方法），再针对每个问题，定位原文中的关键信息句，提取对应内容作答；第5题为开放性问题，结合原文提到的护牙方法，用通顺的英语表达即可。
【解析】1. 问题询问全国爱牙日的时间，定位原文第一段“So we celebrate National Love Teeth Day on 20 September.”，提取时间信息作答；2. 问题询问6岁以下儿童的乳牙数量，定位原文第二段“By age 3 or 4, most children have 20 baby teeth.”，提取数量信息作答；3. 问题询问使用牙线的原因，定位原文“What we can do”部分“Use dental floss（牙线）for your teeth to make them cleaner.”，提取原因作答；4. 问题询问更换牙刷的频率，定位原文“What we can do”部分“Get a new toothbrush every three months.”，提取频率作答；5. 问题询问日常护牙的方法，属于开放性问题，可结合原文提到的护牙建议（如刷牙、少吃甜食等）用英语作答，言之有理即可。
【答案】1. On 20 September.
2. Twenty/20.
3. To make our teeth cleaner.
4. Every three months.
5. I brush them twice a day./I don't eat too much candy.（言之有理即可）
【知识点】英语阅读理解、细节信息提取
【点评】本题为基础的英语阅读细节题，主要考查学生快速定位原文信息的能力，整体难度较低，只要认真阅读原文，准确提取对应信息即可完成作答，第5题的开放性设置符合日常护牙常识。
【难度系数】0.9
