单选题It is common practice for students to take the initiatives to get contacts with business bodies and find a job before graduation, and the efforts of which are mostly time-consuming and sometimes ______ some unhealthy social tendencies. A. foster B. furnish C. nurish D. cultivate

单选题The meridians of longitude are imaginary great circles drawn from pole to pole around the earth. By international agreement, the meridian of longitude passing through Greenwich, England, I numbered zero. The earth is divided into 360 degrees, and the meridians are numbered east and west from Greenwich. There are 180 degrees of longitude east of Greenwich and 180 degrees in the westerly direction. New York has a longitude of 74 degrees west which means it lies on the 74th meridian west of Greenwich. Since the sun appears to travel around the earth in 24 hours, it will move 360/24 or 15 degress in one hour. This reasoning can be used by navigators to determine their longitude. Image that we have set sail from Greenwich, England, after having set a very accurate clock, or chronometer, to the local Greenwich time. As we travel westward toward New York, we notice that the sun is going "slower" than our chronometer. At the time that our timepiece reads 12 o"clock, the sun has not quite reached the zenith. As a matter of fact, when our clock reads noon, what it really means is that it"s noon in Greenwich, England. Our clock continues to tell us the time, not at our present location, but at Greenwich. Let us wait until the sun is directly overhead (noon oat our location) and then read the time on our clock. Suppose it reads I o"clock. This means that there is one hour"s difference in time between our longitude and that of Greenwich. As we mentioned earlier, this corresponds to exactly 15 degrees of longitude, so our longitude must be 15 degrees west. The world is divided into 24 time zones, and each zone corresponds to 15 degrees of longitude. New York is approximately 5 time zones west of Greenwich, so the time difference must be about 5 hours. By maintaining chronometers on Greenwich time, ships can determine their longitude on any sunny day by merely noting the difference in hours between Greenwich time and local sun time and multiplying this difference by 15 degrees. Of course, longitude gives only half of the information needed to determine our precise location. We must also know our latitude, which tell us how far we are north or south of the equator. The Equator is the zero line for the measurement of latitude. Circles are drawn parallel to the Equator to indicate other values of latitude. There are 90 degrees of south latitude. In the Northern Hemisphere, there is a star called Polaris almost directly over the North Pole. This makes it possible to determine the latitude of a given point by setting our sextant to measure the angle between Polaris, the North Star, and the Horizon. Mathematicians tell us that this angle is equal to the attitude at the point in question. To get an idea of our location, therefore, we need to know the local time, Greenwich time, and the angle between Polaris and the horizon.

单选题The environmental balance among ecological communities is exceedingly complex.

单选题Hunters have almost exterminated many of the larger animals while farmers destroyed many smaller animals. A. wounded B. reduced C. killed D. trapped

单选题The British Constitution is ______ a large extent a product of the historical events described above.

单选题Professor Smith is someone we all ______ .

单选题However, beyond that dolorous picture, there is a revolution at work in world agriculture. A．illusive B．blurry C．reflective D．grievous

单选题Daylight saving time was instituted to increase productivity. A. reorganized B. started C. encouraged D. taught

单选题Based on the text, we know that temperature rises will probably

单选题Some people think more of animals than will of children.

单选题Some workers in the nuclear power station were exposed to high levels of ______． A．radiation B．cancer C．microwaves D．high temperature

单选题Rowdy ______ gathered in the leading thoroughfare, and everything was in such a chao that the mayor had no idea of what to do.

单选题The first watermill was horizontal and resembled a rudimentary turbine.

单选题Among the many subjects in school, mathematics is probably the most ______, depending least on a student's back ground and culture. A. universal B. abstract C. arbitrary D. concrete

单选题It"s a common knowledge that schools should strive to teach the general nature, or the structure, of a subject rather than all the details and facts of a subject.

单选题Prepared though I was to be impressed by the magnificence of the Grand Canyon, when I actually stood at its brink, I was ______ by its magnitude scale and grandeur of beauty.

单选题It was now clear that no such weapons were manufactured and none been found. A. was found B. were founded C. has been found D. have been founded

单选题He was fined $5,000 by city regulators for giving money to an inspector, an incident he later described as ______ .

单选题The "contract" appearing in Paragraph 4 is quite likely referring to ______.

单选题If being carded out successfully, the plan will completely change the traffic conditions in the city.