下列粉尘中属难燃粉尘的是（）A、小麦粉B、锯木屑C、木炭粉D、硬橡胶粉

根据短文内容，选择正确答案。

The Americans eat three meals a day. They have breakfast in the morning, a light (简单的) lunch at noon, and a big dinner at night. They often eat breakfast in a hurry, but they have more time for dinner. Americans drink a lot of water (水), a lot of milk (牛奶), and a lot of coffee, but they don't drink much tea (茶).      Some Americans like to eat in a cafeteria (自助餐馆). They can go there for breakfast, lunch, or dinner. A person takes a knife, a fork, a spoon, and a napkin (餐巾). Then he walks to a long counter. He can see all the food there. He chooses (选择) his meal and puts it on a tray.      Then he pays (付钱) for it and carries his tray to a table. I like this self-service, and the meals are not very expensive (昂贵的) in a cafeteria; they are more expensive in a restaurant.

1．This passage is a mainly about American ______.

[ ]

A．meals B．food C．restaurant

2．______ is the most important meal for Americans.

[ ]

A．Breakfast B．Supper C．Lunch

3．Americans like to eat the food ______.

[ ]

A．in a restaurant B．at home C．in a cafeteria

4．The food in a restaurant is ______.

[ ]

A．good B．expensive C．cheap

5．Which of the following is not right (正确的)?

[ ]

A．Americans like drinking coffee than tea. B．Americans have more time to have dinner. C．Americans put their food on the fork.

某些动物如响尾蛇，是用对光的感应来捕食的，这种光是（　　） A．白光 B．紫外线 C．红外线 D．红光

美国人口出生率统计表1940—1960年

年份	1940	1945	1950	1955	1960
适龄女性每千人生产婴儿数量	81	85	108	118	119

——据艾伦•布林克利《美国史》第826页改编

该材料

A．说明了二战结束后美国女婴的数量持续增加

B．扭转了美国人口出生率长期持续下滑的局面

C．表明了美国政府鼓励生育以促进人口的不断增长

D．意味着消费需求的不断增长和经济的持续发展

一牙周病患者，全口牙拔除两周后即做全口义齿修复，半年后义齿固位差，张口说话易脱落。最可能的原因是

A．人工牙排列偏唇颊侧
B．颌位关系错误
C．垂直距离过高
D．基托边缘过度伸展
E．牙槽嵴吸收

按矿床成因分类，则岩浆气液矿床属于（）。

A.热液矿床

B.火山成因矿床

C.伟晶岩矿床

D.岩浆矿床