电石（主要成分为CaC2，杂质为CaO和CaS）是工业制乙炔的常见原料，某研究性

8岁男孩，自幼反复发作膝、肘等大关节炎，现左肘、左踝及右踝关节均有肿胀，活动受限。父母体健，一表兄有相同疾患。血象基本正常。

该患者的发病与下列哪种情况有关（）

A.血小板功能异常

B.血管功能异常

C.先天性凝血异常

D.继发性凝血异常

E.先天性免疫功能异常

1962年3月，周恩来在中央财经工作会议上针对当时我国的经济形势即兴作了一副对联，上联是“先抓吃穿用”，下联是“实现农轻重”，横批应是[ ]

A．一化三改

B．综合平衡

C．多快好省

D．以粮为纲

离退休人员每年领取养老金资格认证的时间及次数？

Americans have a great love for informality and nowhere is this better expressed than in their love for nicknames (昵称，绰号). Upon greeting strangers for the first time they will quickly introduce themselves by their nickname. These are shortened forms of their given name at birth and reflect the casual relationships which exist among friends and coworkers. Family names are hardly ever used in daily situations and the use of one’s father’s last name is saved only for rare and formal occasions.
In many traditional cultures the use of the family name is seen as a sign of respect. For Americans, however, it’s the nickname which creates an immediate intimacy between two people upon which to build a relationship. By speaking to another on a first name basis and using his nickname, walls are immediately torn down and equality between two people is established.
At work bosses will refer to their employees by their nicknames. Should an employer use a worker’s family name, you can be sure that some kind of correction or serious business will follow.
This love for nicknames can create a sense of closeness between people who are otherwise not related. Even the presidents of the United States have borne nicknames. Abraham Lincoln was known as Honest Abe. John F. Kennedy was known as Jack or JFK and William Clinton has no reservations in letting people know he prefers to be called Bill, but those who look upon him with disfavor may call him Slick Willy.
Not only people but cities often carry their own nicknames. Chicago is called the "Windy City" because of the p winds which come down from Canada throughout the year. New York City is considered the "Big Apple" for reasons which are still obscure to most people including many New Yorkers.
Not every nickname, however, is positive and some can be rather rude and insulting. If someone should demonstrate a certain negative characteristic, a label will soon be attached to describe that person in an unpleasant way.
Likewise a person’s physical traits which are very dominant may lead to nicknames but not necessarily to one’s liking or choice. A nickname, therefore, is a way of identifying or describing someone or something for better or worse.

Why do Americans prefer to use nicknames when addressing one another

A. Nicknames are easy to remember.
B. Americans are a friendly people.
C. Nicknames help build a closer relationship.
D. Nicknames are convenient to use in daily life.

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