【正文】 y way to establish the social rank order. When your dog obeys a simple request of “e here, sit,” it is showing obedience and respect for you. It is not necessary to establish yourself as top dog or leader of the pack（群）by using extreme measure. You can teach your dog its subordinate（從屬的）role by teaching it to show submission to you. Most dogs love performing tricks for you to pleasantly accept that you are in charge. Training should be fun and rewarding for you and your dog. It can enrich your relationship and make living together more enjoyable. A welltrained dog is more confident and can more safely be allowed a greater amount of freedom than an untrained animal.21. Behavior problems of dogs are believe to _______. A) be just part of their nature B) worsen in modern society C) occur when they go wild D) present a threat to the munity22. The primary purpose of obedience training is to _______. A) teach the dog to perform clever tricks B) make the dog aware of its owner’s authority C) provide the dog with outlets for its wild behavior D) enable the dog to regain its normal behavior23. Effective munication between a dog and its owner is _______. A) essential to solving the dog’s behavior problems B) the foundation for dogs to perform tasks C) a good way to teach the dog new tricks D)an extreme measure in obedience training24. Why do pet dogs love performing tricks for their masters? A) To avoid being punished. B) To show their affection for their masters. C) To win leadership of the dog pack. D) To show their willingness to obey.25. When a dog has received effective obedience training, its owner _______. A) can give the dog more rewards B) will enjoy a better family life C) can give the dog more freedom D) will have more confidence in himself Passage TwoQuestions 26 to 30 are based on the following passage: Engineering students are supposed to be examples of practicality and rationality, but when it es to my college education I am an idealist and a fool. In high school I wanted to be an electrical engineer and, of course, any sensible student with my aims would have chosen a college with a large engineering department, famous reputation and lots of good labs and research equipment. But that’s not what I did. I chose to study engineering at a small liberalarts（文科）university that doesn’t even offer a major in electrical engineering. Obviously, this was not a practical choice。 I came here for more noble reasons. I wanted a broad education that would provide me with flexibility and a value system to guide me in my career. I wanted to open my eyes and expand my vision by interacting with people who weren’t studying science or engineering. My parents, teachers and other adults praised me for such a sensible choice. They told me I was wise and mature beyond my 18 years, and I believed them. I headed off to college sure I was going to have an advantage over those students who went to big engineering “factories” where they didn’t care if you have values or were flexible. I was going to be a plete engineer: technical genius and sensitive humanist（人文學(xué)者）all in one. Now I’m not so sure. Somewhere along the way my noble ideals crashed into reality, as all noble ideals eventually do. After three years of struggling to balance math, physics and engineering courses with liberalarts courses, I have learned there are reasons why few engineering students try to reconcile（協(xié)調(diào)）engineering with liberalarts courses in college. The reality that has blocked my path to bee the typical successful student is that engineering and the liberal arts simply don’t’ mix as easily as I assumed in high school. Individually they shape a person in very different ways。 together they threaten to confuse. The struggle to reconcile the two fields of study is difficult.26. The author chose to study engineering at a small liberalarts university because he _______. A) wanted to be an example of practicality and rationality B) intended to be a bination of engineer and humanist C) wanted to coordinate engineering with liberalarts courses in college D) intended to be a sensible student with noble ideals.27. According to the author, by interacting with people who study liberal arts, engineering students can _______. A) balance engineering and the liberal arts B) receive guidance in their careers C) bee noble idealists D) broaden their horizons28. In the eyes of the author, a successful engineering student is expected _______ A) to have an excellent academic record B) to be wise and mature C) to be imaginative with a value system to guide him D) to be a technical genius with a wide vision29. The author’s experience shows that he was _______. A) creative B) ambitious C) unrealistic D) irrational30. The word “they” in “…together they threaten to confuse.” (Line 3, ) refers to _______ A) engineering and the liberal arts. B) reality and noble ideals C) flexibility and a value system D) practicality and rationalityPassage ThreeQuestions 31 to 35 are based on the following passage: Priscilla Ouchida’s “energyefficient” house turned out to be a horrible dream. When she and her engineer husband married a few years ago, they built a $100,000, threebedroom home in California. Tightly sealed to prevent air leaks, the house was equipped with small doublepaned（雙層玻璃的）windows and several other energysaving features. Problems began as soon as the couple moved in, however. Priscilla’s eyes burned. Her throat was constantly dry. She suffered from headaches and could hardly sleep. It was as though she had suddenly developed a strange illness. Experts finally traced the cause of her illness. The level of formaldehyde（甲醛）gas in her kitchen was twice the maximum allowed by federal standards for chemical workers. The source of the gas? Her new kitchen cabinets and walltowall carpeting. The Ouchidas are victims of indoor