单选题{{U}}During{{/U}} many sectors are foundering, the $21 billion videogame-software industry is booming, adding game developers at a rate of 2,500 a year in the United States alone.

单选题 About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen. The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic nitrogen compounds. This comes in handy for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids.

单选题He is always working______he can.

单选题Each species has certain______features.

单选题The origin of the word remains Uobscure/U, but it is certainly not from Greek.

单选题The lenient decision of the dean caused anger among the professors.

单选题The passage implies that until 1869, baseball was played for all of the following reasons EXCEPT ______

单选题To impose computer technology ______ teachers is to create an environment that is not conducive to learning.

单选题 Awarded the Nobel Prize for physics in 1918, German physicist Max Planck is best remembered as the originator of the quantum theory. His work helped usher in a new era in theoretical physics and revolutionized the scientific community's understanding of atomic and subatomic processes. Planck introduced an idea that led to the quantum theory, which became the foundation of twentieth century physics. In December 1900, Planck worked out an equation that described the distribution of radiation accurately over the range of low to high frequencies. He had developed a theory which depended on a model of matter that seemed very strange at the time. The model required the emission of electromagnetic radiation in small chunks or particles. These particles were later called quantums. The energy associated with each quantum is measured by multiplying the frequency of the radiation, v, by a universal constant, h. Thus, energy, or E, equals hv. The constant, h, is known as Planck's constant. It is now recognized as one of the fundamental constants of the world. Planck announced his findings in 1900, but it was years before the full consequences of his revolutionary quantum theory were recognized. Throughout his life, Planck made significant contributions to optics, thermodynamics and statistical mechanics, physical chemistry, among other fields.

单选题______old man had______bad fall. Will somebody send to doctor?

单选题The rules stated that anyone who had held office for three years was not ______ for reelection.

单选题As a result of their frequent litters, rabbits have the reputation of being ______. A. ruthless B. prolific C. practical D. rational

单选题Don't set him {{U}}to{{/U}} talking philosophy or he'll go on all evening.

单选题All of us were impressed by her ______ complexion.

单选题In the eyes of the Americans perhaps the most {{U}}laughable{{/U}} thing Daiwa did was to announce that members of its board of directors would accept responsibility for the affair by taking 30% salary cuts for six months.

单选题______, I picked up the phone and rang my sister in AustraliA．

单选题Martha hag made up her mind to buy her favorite furniture, disregard how much money she would pay.

单选题Many students today display a disturbing willingness to choose institutions and careers on the basis of earning potential.

单选题The advertising industry in today's world does have its share of responsibilities {{U}}in leading people to{{/U}} misconceptions.

单选题I would have finished my paper if it was at all possible, but I was fully occupied the whole of last week.