乳胶罩面涂料的涂盖能力为（）。 A.40-50m2/L B.60-65m2/L C.

       Every country has its heroes. The heroes are the people the nation and especially the young people admire. If you get a list of the heroes of a nation, it will tell you the potential（潜势）of that nation.

If today in America, you ask the high school students to list their heroes, their choice would probably fall into three groups. The first group of heroes would be the rock stars —the people connected with rock music. There is no doubt that such people do have talent but one wonders if one should hold up rock stars as a model (推举…为榜样). The rock stars too often are involved with drugs and their personal life is not all that good. The rock stars are rich and wear the latest fashion styles. However, one should seek more in a hero than such things as money and good clothes.

A second type of hero for the American youth is the sports star. Again you have a person who has a great ability in one area — SPORTS. However, too often the personal life of the sports star is a bit of a mess. Too frequently drugs and drinking are a part of life of the sports star.

A third type of hero is the TV or movie star. This person may have lots of acting talent and is quite handsome. However, the personal life of too many actors is quite sad and they should not be held up as a model for young people.

Today, the rock star, the athlete and the actor all have become the models of the youth in America. Really, do you hear a young person say that his hero is a doctor, a teacher, or a scientist? These people are not rich and do not wear fashionable clothes. However, they are talented people who work hard to make the world a better place for everyone.

What is really sad is that the young try to imitate their heroes. They like to wear the same clothes and follow their styles. If the heroes of today for the American youngsters are only rock stars, athletes and actors, the future does not look too bright.

56. The hero discussed in this article means a person ______.

A. who has done something brave          B. who plays an important role in a play

C. whom people greatly admire            D. who rides the waves and moves with the tides

57. What is true of the groups mentioned in this article?

A. They are not fright but are good-looking.       B. They are rich but are strict with themselves.

C. They are talented in some area but lead an indecent life.   D. They are perfect in every way.

58. American young people will not admire ______.

A. a university professor           B. a popular singer     C. a football player     D. a film actress

59. According to the writer, people should hold up as their model those______.

A. who are rich and wear the latest fashion clothes     B. whose personal life is good

C. who can express people’s feelings             D. who work in the interests (利益) of the people

60. What is the writer’s attitude towards American youth’s admiration for their heroes?

A. He is understanding.      B. He is critical.     C. He is angry.        D. He is uninterested.

X线片示根尖部有约豌豆大的圆形透射影，边界清楚、光滑，有骨白线围绕，中心密度均匀，最可能的诊断为（）

A.根尖周囊肿

B.根尖周脓肿

C.根尖周肉芽肿

D.根尖骨质疏松

E.以上都不是

胃溃疡最主要的症状是

A．嗳气，反酸

B．恶心，呕吐

C．呕吐，黑便

D．上腹疼痛

E．食欲减退

白细胞毒素是由下列哪一种牙周细菌所产生

A．伴放线放线杆菌

B．二氧化碳噬纤维菌

C．广溶血性链球菌

D．齿垢密螺旋体

E．牙龈卟啉单胞菌

食品生产单位卫生管理人员的初次培训时间应不少于多少学时

A．15
B．20
C．25
D．30
E．50