为达到螺纹连接可靠和坚固的目的，要求纹牙间有一定的（）。

化学物质在生产、生活中有着广泛的应用，下列说法正确的是（　　）

A．湖水经沉淀、过滤、吸附等净化处理后，即可得到纯净水

B．农业上为了提高粮食产量，就大量使用化肥、农药

C．可用聚氯乙烯塑料制品包装食品

D．校内用钢架制作的自行车防雨棚应定期喷涂油漆防锈

已知一个样本，27，23，25，27，29，31，27，30，32，31，28，26，27，29，28，24，26，27，28，30，以2为组距画出频数分布直方图

“文史互证”是历史研究的一种重要方法，主要包含两层意义：其一，从史学角度考证诗文，即从历史的层面对古诗文进行周密的考订、辨误和解说；其二，从文学角度阐释历史，即以诗文为史料，通过发现其中时间、地域、人物等历史要素，与史籍所载相参证，从而更全面地把握历史真相。阅读下列材料：

材料一　杜甫的诗有“诗史”之称。《春望》曰：国破山河在，城春草木深。感时花溅泪，恨别鸟惊心。烽火连三月，家书抵万金。白头搔更短，浑欲不胜簪。

材料二　宋代铸造铜钱和铁钱的数量相当大。据《宋史·食货志·钱币》记载：“皇祐中，饶、池、江、建、韶五州铸钱百四十六万缗，嘉、邛、兴三州铸大铁钱二十七万缗。”“江、池、饶州，建宁府四监，岁铸钱百三十四万缗，充上供；衡、舒、严、鄂、韶、梧州六监，岁铸钱百五十六万缗，充逐路支用。”

材料三　(鲁提辖)便去身边摸出五两来银子，放在桌上，看着史进道：“洒家今日不曾多带得些出来；你有银子，借些与俺，洒家明日便送还你。”史进道：“直甚么，要哥哥还！”去包裹里取出一锭十两银子放在桌上。鲁达看着李忠道：“你也借些出来与洒家。”李忠去身边摸出二两来银子。鲁提辖看了见少，便道：“也是个不爽利的人！”（摘编自《水浒传》，书中类似的描写还有很多）

请回答：

⑴联系《春望》简要分析杜甫的诗被称为“诗史”的原因。结合所学知识简述唐诗在题材方面的特点。（4分）

⑵根据材料二并结合所学知识，分析宋代铸钱数额巨大的原因。（4分）

⑶结合材料二、三判断，宋代人们日常生活中使用的主要货币是铜(铁)钱还是白银？简要说明理由。（3分）

Bad teeth can be painful — and worse. They can even be deadly. Infections (感染）of the gums (牙龈）and the teeth can cause bacteria (细菌）to go into the blood system. Those bacteria can increase the chance of a heart attack and worsen the effects of other diseases. And adults are not the only ones at risk. For example, in 2007, doctors in the Washington area said a boy died when a tooth infection spread to his brain. They said it might have been prevented had he received the dental care (牙齿 保健）he needed. He was twelve years old.

Experts at the National Institutes of Health say good dental care starts at birth. Breast milk, they say, is the best food for the healthy development of teeth. Breast milk can help slow the growth of bacteria and acid production in the mouth.

But dentists say a baby's gums and early teeth should be cleaned after each feeding. Use a cloth with a little warm water. Do the same if a baby is fed with a bottle. Experts say if you decide to put your baby to sleep with a bottle, only give the child water.

When baby teeth begin to appear, you can clean them with a wet toothbrush. Dentists say it is important to find soft toothbrushes made especially for babies and to use them very gently.

The use of fluoride (氟化物）to protect teeth is common in many parts of the world. For example, it is often added to drinking water supplies. The fluoride mixes with enamel (法琅质)， the hard surface on teeth, to help prevent holes from forming.

31.According to the passage, bad teeth can be ____________.

A.painful  B. deadly  C.preventive  D.incurable

32.The writer uses the boy's death as an example to show that   _______•

A. not only adults but the young may suffer from teeth problem

B. babies with bad teeth can easily die

C. the doctors should be responsible for the case

D. the boy was not fed with his breast milk

33. What's the main idea of paragraph 4 and 5?

A. How to develop babies' teeth.           B. Why to protect babies' teeth

C. How to keep babies' teeth clean         D. Why to keep babies' teeth clean

34. The passage tells us that _______.

A. Enamel is most widely used to protect teeth in the world

B. Bad teeth may affect the health of adults and the young

C. Breast milk can cure babies' bad teeth

D. Babies' teeth should be brushed once per day

35.Which of the following can be used as the title of the passage?

A. Concerns for Healthy Teeth of the Young  B. Importance of Healthy Teeth of All

C. Causes of Teeth Problem               D. Solutions to Teeth Problem

气升举无力形成的病证是（）。
脏腑功能低下或衰退形成的病证是（）。

A.气逆证

B.气滞证

C.气陷证

D.气虚证

E.气脱证