两个正方形ABCD和ABEF所在的平面互相垂直，求异面直线AC和BF所成角的大小

吸烟者患肺癌的可能性增加，这与下列哪些因素有关（）

A.吸烟的种类

B.吸烟时间的长短

C.吸烟的方式

D.开始吸烟的年龄

E.以上都不是

Years ago, when I started looking for my first job, wise advisers advised," Barbara, be enthusiastic (热情的) ! Enthusiasm will take you further than any amount of experience. "How right they were!

"Nothing great was ever achieved without enthusiasm." wrote Ralph Waldo Emerson. It isthe paste that helps you hang on there, then the going gets tough. It is the inner voice that whispers, "I can do it!" When others shout, "No, you can't!" It took years and years for the early work of Barbara McClintock, a geneticist who won the 1983 Nobel Prize in medicine, to be generally accepted, yet she didn't stop working on her experiments. Work was such a deep pleasure for her that she never thought of stopping.

We are all born with wide-eyed, enthusiastic wonder and it is this childlike wonder that gives enthusiastic people such youthful air, whatever their age. At 90, Cellist Pablo Casals would start his day by playing Bach. As the music flowed through his fingers, his stooped shoulders would straighten and joy would reappear in his eyes. An author and poet Samuel Ulman once wrote," Years wrinkle the skin, but to give up enthusiasm wrinkles the soul. "

Enthusiastic people also love what they do, regardless of money or title or power. Patricia Mellrath, retired director of the Missouri Repertory Theater in Kansas City, was once asked where she got her enthusiasm. She replied, "My father, a lawyer, long ago told me, 'I never made a dime until I stopped working for money.' "

If we can't do what we love as a full-time career, we can as a hobby. Elizabeth Layton of Wellsville Kan, was 68 before she began to draw. This activity ended periods of depression that had troubled her for at least 30 years, and the quality of her work led one critic to say, "I am tempted to call Layton a genius. "

We need to turn the tears into sweat as we go after "what-can-be". We need to live each moment whole-heartedly, with all our senses--finding pleasure in the sweet smell of a back-yard garden, the simple picture of a six-year-old, the beauty of a rainbow.

72. Which of the following would be the best title for the test?

A. Enthusiastic people will never get old.

B. Enthusiasm can make you succeed and enjoy life.

C. Enthusiasm is more important than experience.

D. Enthusiasm can give people more success and fame.

73. Which of the following can best explain the underlined sentence in the second paragraph?

A. Enthusiasm can give you courage and strength in difficult times.

B. If you don't have enthusiasm, you can achieve nothing.

C. Enthusiastic people never consider money and fame.

D. Enthusiastic people can gain great fame and honour.

74. The author mentions Cellist Pablo Casals in the third paragraph to show that _______.

A. music can arouse people’s enthusiasm

B. enthusiasm can give people needed inspiration to succeed

C. enthusiasm can make people feel young

D. enthusiasm can keep people healthy

75. How many examples are given in the passage to show the importance of enthusiasm?

A. Three.            B. Two.              C. Four.             D. Five.

燃烧产生的废气是石化行业污染的主要来源之一。

编译程序分析源程序的阶段依次是（）。

A．词法分析、语法分析、语义分析

B．语法分析、词法分析、语义分析

C．语义分析、语法分析、词法分析

D．语义分析、词法分析、语法分析

E-9冬季停车时，（）塔顶有排放循环水的阀门。

A.T-2

B.T-1

C.T-3

D.D-1