甚者从之

进行过滤操作时，一定要用到的仪器是（　　）

A．酒精灯

B．量筒

C．漏斗

D．水槽

酚妥拉明可用于治疗顽固性充血性心力衰竭的主要原因是其可（）。

A.兴奋心脏，增强心肌收缩力，使心率加快，心输出量增加

B.抑制心脏，使其得到休息

C.扩张肺动脉，减轻右心后负荷

D.扩张外周小动脉，减轻心脏后负荷

E.扩张外周小静脉，减轻心脏前负荷

在市场营销学中，市场需求反映消费者对某一特定产品或服务的 ( )。

A．购买意愿和购买能力

B．购买意愿和偏好

C．效用和价值

D．需要和购买欲望

物流系统的形成与发展就是体现出一种时间成本节约的追求。通过准点供货以满足生产企业“（）”生产的要求。

A．速度经济

B．产量增加

C．零库存

D．产量增加

Americans usually consider themselves a friendly people. Their friendships, however, tend to be shorter and more casual than friendships among people from other cultures. It is not uncommon for Americans to have only one close friend during their lifetime, and consider other "friends" to be just social acquaintances. This attitude probably has something to do with American mobility and the fact that Americans do not like to be dependent on other people. They tend to "compartmentalize" (划分) friendships, having "friends at work" , "friends on the softball team" , "family friends" , etc.

Because the United States is a highly active society, full of movement and change, people always seem to be on the go. In this highly charged atmosphere, Americans can sometimes seem brusque (无礼的) or impatient. They want to get to know you as quickly as possible and then move on to something else. Sometimes, early on, they will ask you questions that you may feel are very personal. No insult is intended; the questions usually grow out of their genuine interest or curiosity, and their impatience to get to the heart of the matter. And the same goes for you. If you do not understand certain American behavior or you want to know more about them, do not hesitate to ask them questions about themselves. Americans are usually eager to explain all about their country or anything "American" in which you may be interested. So much so in fact that you may become tired of listening. It doesn’t matter, because Americans tend to be uncomfortable with silence during a conversation. They would rather talk about the weather or the latest sports scores, for example, than deal with silence.

On the other hand, don’t expect Americans to be knowledgeable about international geography or world affairs, unless those subjects directly involve the United States. Because the United States is not surrounded by other nations, some Americans tend to ignore the rest of the world.

According to the passage, Americans tend to ignore the rest of the world because ().

A. they are too proud of themselves

B. they are not interested in other countries

C. they are too busy to learn about other countries

D. their country does not have many neighboring nations